I have one from Nashbar. If you aren't running V brakes but still have the hook ups, it probably would install fairly easily. Mine came with a couple of screws for the V brakes, but they were extra long to accommodate the brakes as well. If you're bike doesn't have brake bosses at all, you'll have to get creative.

I like the rack. It's not heavy duty, but it's come in handy a number of times. And if I wasn't running V brakes, I might be willing to load it up even more, because if it broke, it wouldn't take my brakes with it.