HEATHER LOCKLEAR just can't sit still. Since her debut in the 1980s as trashy Sammy Jo in ABC's Dynasty, Locklear has been working nearly nonstop. She single-handedly saved Fox's Melrose Place, then added spice to ABC's Spin City. What next? A vacation? Nope. Warner Bros. is developing two projects�a sitcom and a drama�for Locklear. This time, she'd be the top banana. "We're looking at something meatier than her role on Spin City," says our insider. We can't wait.