One new site today called HolyFile. They have an old games section that looks very promising.

I received an e-mail some time ago from Abandonia stating that they added an old warez (status) search engine to their site. I apologize for not mentioning it earlier. Basically the search engine allows you to enter in the name of a game and it will tell you if it is still sold (and if so, where). It's really refreshing to see new features like this being developed again.