Originally Posted by mechBgon
Oh, and if you want to try fixing it yourself, the worst-case scenario is that you break the replaceable derailleur mount. Grab it with a big pair of Channelock pliers while the derailleur's still bolted into it (to preserve the threaded hole) and bend it back so it's in-plane with the bike. When you install a new derailleur, make sure to set it up right:
http://www.parktool.com/repair/readhowto.asp?id=64
That's the way I'd go about it, but I would recommend using an adjustable wrench instead of Channelocks. It offers better control, less marring, and will prevent you from possibly bending it along an axis that isn't intended (from friction twisting parallel to the face).