yep, as akira beat me to it- 911 tabs is the site I always use.
Its basically a tab search engine, and it pulls in tabs for all the big sites. True, usually the best tabs are found at Ultimate Guitar, if that site doesnt have it, 911 will probably find it on another site.
...only annoying thing is that they don't thin out the duplicates. Like, you'll find the same tab on all the sites, and if that not the one you want, it can get on your nerves.