|The usual way to to buy a router, you can either buy a wired router or wireless router, although on a wireless router you can actually wire you computers to it as well as connect them wirelessly, just to confuse you! You might say well what's the point of a wired only router, answer is that wireless routers are still fairly new technology(well give or take 10 years :)) and wired only ones are being taken over by wireless routers. Wired only may have some benefits over wireless although i can't really think of any at least for a "home grade" router.|
So really a wireless is "best of both worlds" pretty much. I would recommend a wireless one, there are loads or brands and loads of models within each brand.
You could however also cable your two PCs directly together using an ethernet cross over cable and enable internet connection sharing, a drawback of this is that both PCs must be on for the second PC to have the internet, the second PC being the one that is not directly plugged into the modem rather the first PC is directly plugged into the modem and the second PC plugged directly into the first PC bit like chaining them together.