Mraw, we use OS X Leopard, that's version 10.5. So you have 10.3 (Panther)? Yeah... That's a bit old, but it's not bad. There's just some extra features and stuff in Leopard, but I think you can buy Leopard and install it if you want. :)
Bootcamp does not work on that mac, unfortunately. The fact is, bootcamp can only run on an intel-based mac. That's the new ones. So you can't play PC-games... If bootcamp is free? Yes, it follows on every intel-based mac, so all you need then is windows XP or Vista.
What is the name of the Mac? Just iMac?