I am usually skeptical of these types of apps, especially free ones, but after reading the reviews I decided to give it a try. It was extremely easy to use and worked PERFECTLY on the very first try. It scanned 5000 photos in about 10 seconds. I was able to remove 870 photos and save 1.78GB of space in less than 5 minutes. The app does a fantastic job of showing you what is a duplicate and what will be deleted. It even uses a double confirmation sequence to make you feel at ease about deleting your precious photos. Nice job on this app guys!
mattolpinski about Duplicate Cleaner For iPhoto