Networking our 2 PCs via wirless router

Have just got our second machine back having been rebuilt after a disk crash. My partner has been using my machine and is filling the hard disk with games (part playes). I was thinking about trying to network them together using our wireles router to move all the games to the other machine. Is this possible, how easy/difficult is it. Would I be better off using the NIC cards and a cable please ??