Pet Adoption Website?

A little kitten that lives outside my apartment was recently attacked (maybe by a possum?) He was in very bad condition: A huge chunk was bitten out of his side, and maggots were growing in it, he couldn't eat and was barely able to breathe because of a respiratory infection.

Of course we took him to the vet, and although he's still being held there, they think he'll recover! I would love to keep this little guy, but I have a very spoiled cat who does not want any new playmates. The only No-Kill shelter in my area is full and not accepting any new pets. I'm going to place an ad on Craig's list, and also leave a flyer for him in the Vet's office.

Can any body suggest other websites that you can post adoption ads on for free? After all he's been through, I really want to make sure he finds a good home.