All of a sudden, the amphitheater business is big business.

Several companies across the country are scrambling outdoors to capitalize on what they see as a profitable new market.Fiddler's Green in Englewood, Colo., is the latest entry, built by California-based entertainment giant MCA Inc. But similar ventures are being proposed for Dallas, Phoenix, Atlanta, Miami and Palm Beach, Fla.

"Some of companies are convinced they can make a tremendous amount of money," says Russell Johnson, the owner of Artec Inc., a New York-based design company that works with amphitheater builders. "It doesn't cost all that much to build these things."

For the most part, they're riding a national trend of rock bands preferring to play outdoors and audiences preferring to be outdoors.

"It's easier for performers to travel in the warmer months without fear of a snowstorm knocking off a date," says Cathy Rochefort, a spokeswoman for the 15,000-seat Great Woods Center Arts near Boston.

What's more, stadium concerts have fallen somewhat into disfavor with audiences.

Houston-based Pace Management Inc. has built at least two amphitheaters and reportedly is proposing more. Pace owns the 15,033-seat Starwood amphitheater at Nashville but recently sold its interest in Houston's Southern Star amphitheater to Six Flags Corp.

MCA Inc. is proposing amphitheaters in Dallas and Atlanta after having finished Fiddler's Green in time for this summer's concert season. It already owns Universal Amphitheater in Los Angeles, which MCA Concerts president Marc Bension says "does more shows than any other amphitheater in America."

Zev Bufman, a Miami-based developer who has plans to build five amphitheaters around the U.S., predicts stage shows will be the newest big market: "In the 1990s, Broadway productions will go outdoors."

But some worry about overbuilding. Atlanta already is grappling with two amphitheater proposals, and the Costa Mesa, Calif., area has two relatively new amphitheaters sharing a limited market.