StarDestroyer.Net BBS

My grandfather died a while back and since I am the best person with computers that the family knows I've started sorting through all of his digital photos. It's pretty horrible to go through the thousands of them by hand so I was wondering what the best freeware software is out there for indexing and cross-referencing photos?
I'd like to be able to have them tagged for easy searching, for example I could search for ones that are landscapes or has X person, or animal shots.

Most of the stuff google shows up isn't free or doesn't seem to do what I want to do.

Few programs will be able to auto tag the photos (actually, I'm not aware of any). If you just want software that can do tagging, Windows Live Photo Gallery and iPhoto are quite possible.

Thanks, I'll try those out. And an automatic sorter would be awesome but probably won't be coming out for a very, very long time.