While donating is altruistic. Sometimes it makes more sense to sell... Your net tax break will only be the fmv of the car (most use blue book) x your marginal tax bracket (say 28%). Just something to think about if you've got a viable vehicle. If it's a piece of crap, however...
Also, just make sure the title gets all straightened out. I've heard more than my fair share of horror stories!
alright my carefully guarded secret is out... ballet doesn't pay the bills, so I'm a nerdy accountant :p