On a related topic - are there are good programs out there that would let someone, not extremely computer literate, wipe the hard drive so it can be donated along with the computer?

I hate the thought of removing and trashing the hard drive, although I do realize it is the absolute safest way to make sure no one else can read anything that might have been left on the hard drive. But I hate the thought of leaving personal stuff on the hard drive that might be recovered by who knows who.