They locked up mob boss Paul Vitti in Sing Sing and that's where he sang sang- croaking tunes from Westside Story and carrying on in a way that convinces the feds Vitti is better suited for the nut house than the Big House. Better yet, they conclude, let's release Vitti into the custody of his therapist Ben Sobel. The boys are back and so is the fun when Robert De Niro (Vitti) and Billy Crystal (Sobel) reprise their ANALYZE THIS roles. This time, Vitti is ready to find gainful employment and go straight. Or so he says. But can high-anxiety Sobel believe Vitti, especially when guys like Lou the Wrench keep showing up? In the words of more than one sage who knows his dese from his dose: fuggedaboudit!