I have a really old 16M flash cart for Game Boy that connects to a PC via a parallel port. Obviously, they don't make computers with parallel ports anymore, so I might get this.
Well, you CAN still get computers with parallel ports... but instead of buying a new computer, you could just get something like this (or this if you don't have any PCI slots). There are also some USB solutions available... though most of those seem to be meant for printers, so I'd be a little skeptical about odd hardware working with them.
--Zero