Quote Originally Posted by Lars Noodén View Post
It's a good system. You got a good deal.

Leopard (10.5) is the last OS X version to support PPC. So if you want OS X, that's your only option.

If you want Linux, then you have Debian and several flavors of Ubuntu such as Lubuntu to choose from.
+1 to this. If you can get your hands on Leopard that'd be a nice upgrade. It's a really nice OS overall, too.