iTunes Dupes Barrier allows you to search the duplicate songs inside the iTunes and iPod songs' databases. It was designed to do searches of duplicate songs in an average-sized iTunes' library, not a huge one. It has only four filters with which to search, and the possibility to trash found items exists without an option to help you to locate them automatically in the found list.

Requirements:
OS X 10.3.9 -10.6
Universal Binary