freshmeat.net has a few Dvorak typing tutors. My favorite of the ones I’ve tried is dvorakng, a curses-based program that keeps stats on what keys you miss the most.
Mike Rollins, a guy I work with, let me have his old fancy Dvorak-labeled keyboard. This is like the most ergonomic keyboard ever. Each hand sits in a little bowl of keys. You can reprogram the keys to do different things. There is no normal backspace key: you hit it with your thumb instead.
I don’t think I’m going to keep using it, though, because it moved the Dvorak =, /, and \ keys to weird locations, and I don’t want to get any more dependent on weird keyboards than I already am. I can’t take over other people’s keyboards right now (which may be a Good Thing) because I can’t type QWERTY right now. In a few weeks I’ll re-learn it, after I’m solidly entrenched in Dvorak.