Have duplicate files and packages....

You can search for duplicate files and packages; by the owner application, content, type, creator, extension, time modified, time created, name, label, visibility and date/age. You can also search by the tag, duration and bit installments of MP3 and AAC sound files and EXIF metadata, search the contents of the iPhoto, Aperture, iTunes, iPod databases and Mail mailboxes, and synchronize deletions with iPhoto, Mail and iTunes.

- Tidy Up! allows you to search for duplicate folders; by name, date modified, date created, label visibility, empty folders, their contents and more.
- Many more features.

Link:
http://www.apple.com/downloads/macosx/system_disk_utilities/tidyup.html