Steering Wheel Radio Controls

Has anyone added/converted their steering wheel to interface with an aftermarket radio to incorporate the controls into the wheel? If so, what switches did you use, and what does it take to get the radio to "talk" to the switches? I've been looking at other Ford steering wheels (Exploder and the like) to see what could be found that already has switches mounted. This would be for an '01.

Thanks for your help,
Nathan