BOB ABERNETHY, anchor: International humanitarian crises have inspired high profile evangelical leader Rick Warren to launch a wide-ranging new global initiative. Warren is pastor of Saddleback Church, a megachurch in Southern California. But he's best known for his mega-selling book, THE PURPOSE-DRIVEN LIFE. Since its release in 2002, it has sold more than 25 million copies, making it one of the best-selling books in history. Warren and his wife Kay are donating most of their earnings to help heal some of the world's worst ills. Kim Lawton caught up with them in Toronto, Canada at the end of a month-long global tour.

Dr. RICK WARREN (Pastor, Saddleback Church, Lake Forest, California and Author, THE PURPOSE-DRIVEN LIFE): How are you guys? How are you doing? Thanks for being here.

KIM LAWTON: It's a timeless Sunday ritual. After church, the pastor greets the worshippers. Never mind that this pastor authored the best-selling book in the world for three years running or that on any given Sunday more than 20,000 people attend his services. Rick Warren says Saddleback Church keeps him grounded.

Dr. WARREN: That's why I've never moved from where we started the church. People say, "Oh, that's old Pastor Rick. He's been there nearly 30 years."

LAWTON: "Old Pastor Rick" may be a local minister at heart, but now he's going global -- leveraging his position as megachurch leader and best-selling author to mobilize churches to tackle some of the biggest problems in the world.

Dr. WARREN: Nothing comes close to the size of churches -- the broadest distribution network, the most volunteers, local credibility -- all these different things that make the church poised to deal with these issues of spiritual emptiness and corrupt leadership and poverty and disease and illiteracy, which are problems that affect billions of people, not just millions.

LAWTON: Warren and Saddleback members have been developing a model of action in Rwanda that they hope will be applied by other churches in other places. Warren calls it the P.E.A.C.E. Plan, one of his many trademark acronyms and lists.

Dr. WARREN: P.E.A.C.E. stands for P-E-A-C-E: Partner with congregations or Plant a congregation, if there's not one there; Equip servant leaders; Assist the poor; Care for the sick; and Educate the next generation.

LAWTON: He and Kay, his wife of more than 30 years, are not deterred by criticism that their agenda is too broad and perhaps a bit naive.

Dr. WARREN: I think we often set our goals too small and try to accomplish them too quickly. This is not something we intend to do in five years or 10 years.

KAY WARREN: Or by ourselves.

Dr. WARREN: Or by ourselves. It's giving the rest of our lives and mobilizing the network that's already there.

LAWTON: It's a path they never could have imagined when they first met as teenagers.

Ms. WARREN: I know it sounds really cheesy, but it's the truth. I knew when he was 17 that there was, that God had his hand on this young man in a way that I had not experienced in other people that I had met. Of course, I had no idea what that was going to look like. I just knew that --

Dr. WARREN: Neither did I.

Ms. WARREN: No, we had no idea. We're both, you know, from small churches, lower middle income families. I mean, we had no idea. I say it's both exhilarating and terrifying. It's exhilarating because we're partnering with God, and it's terrifying because we're partnering with God, you know? It's both of that.

LAWTON: Warren divides his ministry in 10-year increments. In the first decade, he focused on Saddleback. The church that he and Kay started in 1980 is now spread over 120 acres. It's affiliated with the Southern Baptist Convention, although the word "Baptist" doesn't appear on any signs. A network of small groups keeps people connected to the huge congregation and each other.

There are multiple services every weekend. Worshippers can choose from eight venues. There are different atmospheres and styles of music, all with the same sermon broadcast over a live video feed from the main sanctuary.

UNIDENTIFIED MAN (at microphone): Well, let's join Pastor Rick and the other venues for the worship sermon.

Dr. WARREN: (to church): Good to see you guys. My name is Rick Warren. I used to be a pastor here. I've been on the road for 48 days, 14 countries, 34,000 miles. I have a lot of extra air miles if anybody needs some credits.

LAWTON: In the second decade, the ministry went national. Based on Saddleback's success, Warren began training other pastors, borrowing heavily from management guru Peter Drucker. Then, in 2002, he wrote THE PURPOSE-DRIVEN LIFE. Some critics called it a simplistic, slogan-filled view of the faith, but it became a publishing phenomenon that even Warren can't fully explain.

Dr. WARREN: (in Pittsburgh speech): Now let me just be honest with you folks. There's nothing new in the book THE PURPOSE-DRIVEN LIFE that hasn't been said in historic Christianity in the last 2,000 years. I just put it in one book and said it in a real simple way.

LAWTON: The book's runaway success brought him tens of millions of dollars and worldwide attention that Warren says scared him to death.

Dr. WARREN: (in Pittsburgh speech): So I began to pray about this, what I called the stewardship of affluence and the stewardship of influence. What do I do with the money and what do I do with this notoriety?

LAWTON: It was Kay who became the catalyst for what came next. While recovering from treatment for breast cancer in 2002, she randomly picked up a magazine article about the more than 12 million children in Africa orphaned by AIDS.

Ms. WARREN: It was as though someone just ripped this huge blindfold off my face, and it haunted me. I realized that God was calling me to care about people with HIV, and I did, and it began this incredible journey. It changed the whole direction of my life. It changed what I care about and --

Dr. WARREN: I'll say.

Ms. WARREN: -- what I talk about, what I think about, what I read, what I do.

Dr. WARREN: She's a very disturbed woman.

Ms. WARREN: Yeah. I became a seriously disturbed woman, and it started so small and then has mushroomed into a huge ministry.

LAWTON: HIV/AIDS has become a defining issue for the Warrens. They've made it part of virtually every aspect of their ministry -- at their church, across the U.S., and around the world. They began a new HIV/AIDS foundation which ministers to those suffering from the disease and urges evangelical churches to get more involved with the issue.

Ms. WARREN (at church concert): Do you know how completely out of the ordinary it is for a church to be full on World AIDS Day saying, "We care about people who are HIV positive"? It's amazing. Amazing.

LAWTON: Last year, on World AIDS Day, they sponsored an awareness concert at Saddleback with high profile musical guests, including Wynonna Judd. They also organized a conference urging church leaders to overcome the stigma that often surrounds HIV. As part of it, Warren discussed his own risk factors.

Dr. WARREN (at World AIDS Day briefing): I've never had sex with anybody except my wife. We were both virgins when we got married, and it is great, by the way. Can I say that?

Ms. WARREN (at World AIDS Day briefing): Well, you did.

LAWTON: Then he publicly took an HIV test to demonstrate how easy and important it is. The test was negative. In August, the Warrens attended the XVI International AIDS Conference in Toronto, where Rick was the keynote speaker at a forum for faith-based groups.

Dr. WARREN (at Toronto conference): So, I wasn't wasting my life, but God just said, "Rick, you don't care about the people I care about the most. I care about the poor and the sick, and the needy, and the oppressed." And I said, "God I'm sorry, and I will use whatever affluence or influence you give me to speak up for those who have neither."

LAWTON: And no matter where it takes him. He raised eyebrows earlier this summer with reports that he planned to preach in North Korea next spring.

Dr. WARREN: I knew that I'd be criticized. And people say, well, you're being a pawn. You're being used, and things like that. Well, the truth is, I want to get the good news out.

LAWTON: He doesn't want to get pigeonholed by politics, despite his well publicized friendship with President Bush.

Dr. WARREN: I want evangelicals to be known not for what they're against, but what they're for. My agenda is to be as big as the agenda of Jesus.

LAWTON: Warren puts his money where his mouth is. With the proceeds from his book, he repaid Saddleback for every penny they had paid him in salary, and the Warrens are reverse tithers. They give away 90 percent of their income and live on 10.

Dr. WARREN: I find the generosity the easiest part. I find the most difficult part is this constantly being under the spotlight. I think being under the spotlight all the time blinds you. I don't think it's good for your character.

LAWTON: He says he tries to stay disciplined in daily Bible reading and prayer, taking frequent stock of where he is spiritually.

Dr. WARREN: The one that can run out for me the easiest is the emotional gauge, which is the gauge that when you're always with people, always giving out. There have been days in the last 38 days when I was in 13 countries that I thought, "If I have to take another picture, or sign another book, or just be compassionate to one more person, I'm going to run out of energy."

LAWTON: The Warrens say Kay's battle with cancer reminded them of the frailty and preciousness of life. Now that doctors say she's fine, they want to make every moment count.

Dr. WARREN: You know, when the book came out, we could have gone and bought a tiny island and retired and had people serve us drinks with little umbrellas. But, you know, when you write a book and the first line is, "It's not about you," then you figure, okay, the money's not for you that comes in, and the fame's not for you either. You're supposed to use it for good and for God.

LAWTON: I'm Kim Lawton in Toronto.