And this year's award for best acting by a midriff goes to Spears, for her screen debut in Crossroads. Not since Maria Montez (of 1944's Cobra Woman and other camp classics) flounced about in island girl getups has a bare waistline drawn such admiring attention as it does in this congenial if unexceptional teen coming-of-age drama.

Spears, the honey-blonde singer who, since 1999, has ruled the pop charts with suggestive teenybopper hits ("Oops! . . . I Did It Again"), plays Lucy, an 18-year-old Georgian. After graduating as her high school's valedictorian (mercifully, we're spared her speech), she heads cross-country with two childhood friends (Saldana and Manning). Lucy's objective: a visit to the mother (Kim Cattrall) who abandoned her and her dad (Aykroyd) when she was 3. The movie's objective: female bonding with elementary school paste as Lucy and buds yak about old times and sex, earn cash warbling at a karaoke bar (one guess who sings lead), tipple and confront impending adulthood. Lucy, a virgin, also links up with a caring ex-con (Mount). He sets a poem of hers to music ("I'm Not a Girl, Not Yet a Woman," Spears's new hit single), which beats roses any day.

First seen in bra, panties and socks enthusiastically lip-synching to Madonna's "Open Your Heart," Spears doesn't embarrass herself here, but she's rarely more than pleasantly bland. Making a more vivid impression is Manning as Lucy's pregnant pal; she comes across as a junior Amy Madigan, complete with scratchy voice and a ferocious energy. As Lucy's beau, Mount maintains an air of resigned patience, like a male ballet dancer awaiting the next lift. (PG-13)

Bottom Line: She's not a joke, not yet an actress