True retroheads respect the Commodore 64. It's the first system I ever owned, and it kicked ass for its time. While it's obviously been outclassed now (and most of the games were crap), the Commodore 64 iPhone App has been an incredibly popular addition to the iTunes Store. It's about to get even more popular, because now it's free!
Previously available for $4.99, the App can now be downloaded for the wonderful price of bugger-all. This might not be the case forever though, so you're advised to hop on iTunes at the first available opportunity and nab it. I haven't even picked up an iPod Touch yet but I've had to download it, just for when the occasion arrives. I suggest you do as well.
The only downside is that Wizball is a paid title. Still, Wizball is the dog's bollocks, so if you're feeling wealthy, I reckon you can't go wrong with picking it up.