You can also get one of these to use wireless 360 controllers with your PC:
That's what I have and it works great. Most modern games even detect when you're using the 360 pad and change all the control prompts to show 360 buttons, like so:
Steam Community :: mjc0961 :: Screenshots
Steam Community :: mjc0961 :: Screenshots
If you don't want to get that receiver though, you have to get a wired controller like Dark Knight linked to. The cord from a Play and Charge kit doesn't allow for button inputs, it just charges the battery while the controller sill operates wireless, so you can't plug in a wireless controller to a computer with that cable and have it work as a wired controller.
You can also do that MotionJoy thing for PS3 controllers. I tried it once. It worked the first time, and no matter what I did I couldn't get it to work again. It really is hit and miss.