IT ALL STARTED BACK in 1997 when Courtney Thorne-Smith traded the straight-faced bitch slapping of Melrose Place for the slapstick hair pulling of Ally McBeal (Fox, Mondays, 9-10 p.m.). Suddenly, a gaggle of Melrose babes saw their next logical career move: comedy.
     Before you knew it, Kristin Davis, who had drowned in the apartment-complex pool as the soap's Brooke, was resurrected as Charlotte, the least cynical (and therefore most likable) of the nutty Manhattan bachelorettes on Sex and the City (HBO, Sundays, 9-9:30 p.m.). Not coincidentally, the farce was created by Melrose mastermind Darren Star. And after Fox evicted Melrose last season, two of its female residents moved into ABC sitcoms: Heather Locklear to Spin City (Tuesdays, 8-8:30 p.m.) and Rena Sofer to the new Oh Grow Up (Wednesdays, 9:30-10 p.m.). What's the biggest difference between the genres? "You don't get to make people laugh as much being on a soap opera," says Sofer. "Well, not intentionally anyway."
     So far, Sofer has provided Oh Grow Up with most of its laughs. Her story line is straight out of a daytime drama - her husband left her after admitting he was gay - yet she's managed to wring humor out of such bitter punchlines as "You promised to love, honor, and not go Nancy on me!" "People really had a hard time thinking I'd be able to do comedy," says Sofer, who won an Emmy for ABC's General Hospital before playing psycho ex-cheerleader Eve during Melrose's final season. "I don't mean this in an egotistical way, but what I got on a lot of [sitcom] auditions was 'She's too pretty to play this role.'"
     Good looks certainly haven't stopped Locklear from scoring on Spin as the mayor's new senate-campaign manager, Caitlin Moore. In the first scenes she seemed naive, but Caitlin quickly proved to be as skilled a schemer as Melrose landlord Amanda Woodward. "Let's not get so dramatic," deputy mayor Mike Flaherty (Michael J. Fox) warned her after one cunning maneuver. "This is not some cheesy soap opera." As Spin settles into its fourth slot in as many seasons, Locklear could supply the sparks necessary to push this show past its increasingly tiresome Tuesday competitor, NBC's Just Shoot Me.
     Even dramas are raiding Melrose's hottie closet for comic - and ratings - relief. NBC's would-be thriller Profiler (Saturdays, 10-11 p.m.) is replacing departing star Ally Walker with Jamie Luner (Melrose sex kitten Lexi Sterling). "Knowing me, they wanted to enhance the show with a little bit more humor, not have it be so heavy all the time," explains Luner. Good thinking: The way-too-intense Walker often seemed scarier than the criminals she was hunting.
     Melrose's males aren't in as great demand, with the exceptions of Rob Estes (club owner Kyle McBride), who's joined NBC's alleged comedy Suddenly Susan, and John Enos III (mobster Bobby Parezi), who pops up on the Oct. 3 episode of Sex and the City as a self-confident, well-endowed fellow nicknamed Mr. Cocky. Still the women grab all of Sex's best scenes, while the guys are treated as mere pieces of meat. Hey, maybe this show isn't so different from Melrose Place after all.
(Additional reporting by Kristen Baldwin and Shawna Malcolm)