Tuneboy is NOT Mac native. It can be run under Virtual PC, but I don't recommend this. It does work, but you will have timeout problems that can corrupt your ECU. This is fixable, but you will need a Windoze box for the fix to work.
Basically the problem with the Mac is the interface between Virtual PC and your USB port. It's too slow. I managed to download one tune to the ECU, but when I tried to download a second tune it timed out in the middle. In order to recover from a failed download you have to have nice fast connection speeds. Suxor. Now I have to borrow a PC laptop every time I want to tweak the tune.
And now, off to school and a room full of naked women. :-D