The best by far is at
http://sb-software.com
(no affiliation, etc. - just LOVE his stuff)
Use his "quadsucker web" AWESOME!
He has the BEST newsgroup robot downloader, sbnews - simply increadible. Every day it has thousands of photos for me to look through, just waiting for me. THen you use his viewer to look through them lickety split and pop them into your category directories on the fly.
quadsucker web is pretty cool though...