Originally Posted by Jerry Garcia
Dip it in gold and frame it. Then never ride it again.
That's only if you have a Hutch.
Points to Darin for suggesting Naval Jelly. That stuff will do the trick. If rust is a big problem in your area (tropical Australian weather near the sea is heaps bad too) then I suggest spraying some WD40 onto a rag, and using that to wipe down all the bits that can rust on your bike. And don't ever leave it outside. Ever.