I purchased AppleCare with my TiBook last month, and the cdrom I received contains TechTool DeLuxe 3.0.2, which can run natively in OS X.
According to the Micromat website, there is an Techtool DeLuxe to TechTool Pro upgrade especially for AppleCare owners (50 bucks).
I would certainly hold off on that one though, until Techtool 4 is out, although I have to say that it's my experience that if you really need hard drive emergency cover, DiskWarrior has never ever let me down.
H