Now that the major networks have ordered their pilots, it's time to meet with the folks who pay the bills. Starting next week, the networks will give advertising types on both coasts a peek at their development prospects. Here's the skinny: CBS will be at the Ed Sullivan Theater in Manhattan March 15, then at Carnegie Hall on May 16. NBC executives will be on the set of The West Wing March 19, then in New York, probably at Radio City Music Hall May 14. The WB is holding court at its Burbank facility March 20, then at the Manhattan Sheraton May 15. ABC's West Coast meeting is scheduled for March 21 (likely on the Disney lot in Burbank), then at Manhattan's New Amsterdam Theater May 15. Fox is hosting a gathering at the Beverly Hills Four Seasons March 20, then aboard the U.S.S. Intrepid ship/museum in New York May 17. Finally, UPN will be on the co-owned Paramount Studios lot March 19, then at Madison Square Garden May 17.