DMG has very basic material (epic progressions for main classes and a few feats)
Expanded Psionics has epic psionic classes and psi-feats
Complete books have epic feats, classes, and a example PrC (careful: the Complete Divine is Cut-and-Paste and still lists Beast Shape as a pre-req feat)
The Wizards 3.5 Update Book (under downloads on mainsite) has epic DMG PrCs and some updates for 3.5 (though pretty bare-bones, no revisions just irons out compatibility and converts monsters)
Draconomicon has some updated Epic Feats in the Dragon Chapter (Two, I think)
Frostburn and Sandstorm both have some Epic Spells
There is some epic stuff in Player's Guide to Faerun, but I don't own that book.
On my other computer, I have a list of each Epic Feat and what books they've been updated in (and necessary changes) If I get a chance, I'll find it and post it if people want. (and its not a no-no).