Connie (Nia Vardalos) and Carla (Toni Collette) are a couple of sloppy, big-haired rubes who want to be Broadway stars. The two have an ''act'' that consists of dressing up in costume and singing happily over-the-top versions of show tunes at an airport lounge; none of the bored travelers on hand pay them the slightest attention. Then, in a variation on ''Some Like It Hot,'' the heroines of Connie and Carla witness a nasty bit of criminal hanky-panky and hightail it to L.A., where they slather on eye glitter and pass themselves off as female impersonators, landing a gig at a drag queen cabaret called the Handlebar. There, without trying too hard, they achieve the drag diva's torch song dream of becoming the women they're ''pretending'' to be. In the real world, they're pathetic nobodies, but in the cheesy sequined demimonde of cross-dressing musical kitsch, they're stars!
The women-posing-as-men-posing-as-women gambit was scarcely outrageous -- or very funny -- when director Blake Edwards tried it in 1982 in ''Victor/Victoria.'' If anything, it's milder here. Nia Vardalos, with her playful come-hither saucer eyes, is an appealing actress, and Collette, who looks like Picasso's Dora Maar on the Atkins diet, is a vaguely scary one. In their offbeat-sitcom way, they're a vivid enough team, yet Vardalos, in her follow-up to ''My Big Fat Greek Wedding'' (she wrote both scripts), crams the movie with as many self-esteem lessons as an ''Oprah''/''Dr. Phil'' marathon, and she manages to do for men in wigs and dresses what she did for Greeks: turn them into disposable cartoons. The heroines toss their curls and say ''Fabulous!'' and the movie is broad enough to actually feature a repeated pun on the phrase ''It's a drag!''
That said, when Connie and Carla perform their belt-to-the-rafters versions of ''Maybe This Time'' and ''Don't Cry for Me, Argentina'' and ''What I Did for Love,'' this chintzy contraption comes to shameless, spangly life. Considering how badly their act went over in airports, you may wonder at their ability to bring down the house, but the surprise -- and intermittent delight -- of ''Connie and Carla'' is the way that it taps into the everybody-is-a-star passion of the new sing-along culture. The film presents operatic drag queen performance, in its bombast and overkill, its fever of putting on a persona and letting it shine, as the original, underground version of ''American Idol.''
Connie befriends Peaches, an impersonator so maudlin with self-loathing that he might have stepped out of ''The Boys in the Band.'' He's a pre-Stonewall relic, yet the tender stage actor Stephen Spinella makes this cry-baby masochist work. David Duchovny plays Peaches' very straight brother, who finds himself strangely attracted to Connie, even though he thinks she's a man. Had the film pushed the implications of this a little further, it might have been an eye-opening romantic comedy, instead of a droopy one that perks right up every time somebody sings.