You'll need a Wii remote or "Wiimote" to start with. Normally they are about $40, in the end that is not too bad for a pretty awesome sensor. Otherwise you can check out ebay or elsewhere for used or broken Wii remotes.
You'll need to rip apart the case. It has some crazy three pronged screws. I didn't want to completely trash the case so I made a small tool to take it apart.
Now you need to desolder the 8 pins and the 2 struts holding the camera on the board. I used some desoldering braid. It wicks the solder away and makes it easy to get the camera out. Be careful, don't break the camera!
How to use desoldering braid: http://www.youtube.com/watch?v=AcbezX8TrOU
You might want to keep the rest of the parts. You might be able to scrap other parts. Also, If you decide later to use the Wiimote again, you could always put the camera back in.