You can get a paint stripper wheel from Auto Zone that will remove surface rust (Just pop it in a drill and go at it). I think there is also some stuff you use to get rust out of a gas tank at Auto Zone for inside the frame.

I have no faith in human perfectability. I think that human exertion will have no appreciable effect upon humanity. Man is now only more active - not more happy - nor more wise, than he was 6000 years ago. Edgar Allan Poe