As iTunes doesn´t provide a function to update/synchronize your music collection with it´s own database, I´ve written a small utility for that purpose. Well, you may use ´Consolidate Library´ of iTunes, but this is a typical Mac´ish behaviour letting one application control almost your whole life. I don´t like that too much, so better let my app control your life... :)

Even though I think that most severe bugs should be fixed by now, I still recommend to backup your iTunes database (´iTunes 4 Music Library.itl´ and ´iTunes Music Library.xml´) before playing around too much.