This web page amounts to the largest single source of "funny cat photos with text" internet pictures I have ever encountered. Also, I has a cookeh. Link. Oh, wait, here is another even larger collection: Link. (thanks, Andrea James, and Charlie)
Reader comment: Nebe says,
Lots more cat pix with funny captions (a la Ceiling Cat or O RLY? owl) at icanhascheezburger.com.