Duplicate file finder?

[Nutcase]

Is there some software that can find duplicate files, even with different file names? My old blueyonder webspace finally croaked, and I've a LOT of pics I need to rehost, but over the years they've ended up all over the place, and nosing round my comp there's copies all over the place too (whenever I changed to a new hard drive I'd copy anything needed from the old one - and to give an idea of how long ago this has been going on, one directory is called 300meg drive!!!!).

Basically, all my files are in a mess So I'd like to clear as many as I can before I start trying to move them all into a sensible order...