Spirituality is a growth industry. And nothing illustrates that better than the burgeoning crop of colossal sanctuaries sprouting up in suburbs across the land. Having experienced explosive growth over the past decade, these mostly nondenominational megachurches are employing decidedly entrepreneurial practices. Slick marketing, high-tech production values, and a practical message have created a product that plays well to today's fickle churchgoer. Megachurches -- defined as congregations with more than 2,000 members -- number close to 600 in the United States. Senior minister Bob Russell of Southeast Christian Church preaches to some 15,000 people on an average weekend. Russell's church, which is located in Louisville on a sprawling 110-acre facility, has a yearly budget of more than $18 million. For Russell, the marriage of media and ministry is a natural. "It would be wrong for the church not to use every technological advantage to spread the gospel," he says.