Tool to compare images

[dsbomb]

I love Offlinelist for managing my DS games. Now I want to find something similar to just perform simple tasks on other ROM images (NES, SNES, etc). Say, take an md5sum of all the files, tell me which are duplicates, etc. Is there a site that has the XML files OfflineList uses for other old systems, or a generic app that can do something like this? If all else fails, I suppose a download of cygwin and I can mash together something with md5sum and sort...

 

[FAST6191]

http://www.advanscene.com/ does a couple of dats and offline list has a few other system dats. no-intro also have a dat or two to their name.
main site:
http://www.gbadat.altervista.org/
offline list site:
http://nointro.free.fr/
they only do crc32 though, md5 and sha1 are only just making inroads into mainstream dat making.