"WhirlGirl," an advertiser-supported action series set to launch on the Web July 27, is promoting itself with a 15-second TV spot breaking July 20 in major markets including New York, Los Angeles, Chicago and San Francisco during "Seinfeld," "Baywatch,""Mad About You" and other programs. "WhirlGirl," produced by Visionary Media, features a post-Generation Xer who's trying to save the world from the "media-tech empire."