Finding and removing duplicates in iphoto

Does anyone have any idea how to do this?

Also, one of the frustrating things, I tried to copy ALL my pictures from all my computers to ONE folder, but there were a lot of duplicate file NAMES but they weren't duplicates. This is because I bought a new Panasonic camera in 2008, so all the files it saved have the same file names as my Panasonic camera I bought in 2006.

So... I just need to get my photos organized.

Thank you for your help ahead of time!