Finding Duplicates in Aperture?

A few days ago, iPhoto crashed on me for the last time. Soon after I purchased Aperture 1.5 and hope I'll never have to set eyes on iPhoto again

I am left with a problem though. iPhoto's crash has resulted in me having 2 or 3 copies of many photo's. I could manually delete them, but my library is 20,000+ images strong, and I value my youth

Can anybody suggest an effective way to search a delete duplicates using Aperture?

Many thanks

 

Am currently trying: http://www.dreer.ch/cms/?Current_Projects:PixCompare