This first theatrical outing for the ubiquitous Olsen twins is their take on The Parent Trap meets The Prince and the Pauper. One plays a foster child under the care of a single social worker (Kirstie Alley) whose marital status prevents her from adopting her favorite charge. The other is the neglected daughter of a "bazillionaire" (Steve Guttenberg), who's about to marry a gold-digging socialite (played nastily by Jane Sibbett, Ross's first ex-wife on TV's Friends). The foster kid comes to a charity camp abutting the rich girl's summer estate and--presto--the identical strangers meet, hatch a plan to solve both their dilemmas, and switch identities. Directed by Andy Tennant (Ever After), this PG-rated film features some decent G-rated chemistry between Alley and Guttenberg and surprisingly uncloying performances by Mary-Kate and Ashley. The rating is for mild language. (Ages 5 and up) --Kimberly Heinrichs