Hyperbolic Software has released iTunes Dupes Barrier, a free application that locates duplicate files in iTunes and the iPod. Designed for those Macs running Mac OS X 10.3 and later and iTunes 4.0 and later, the utility determines duplicates by track title, artist, album, and file size.
When you run the program it creates a new iTunes playlist called Duplicate Songs where — as the name implies — songs and their duplicates are listed. It’s then up to the user to return to his or her iTunes library and dispose of the duplicates.
Unlike AppleScript-based solutions such as Doug Adams’ Corral All Dupes, iTunes Dupes Barrier works very quickly — locating duplicates in a matter of seconds.