the best way (if you can find it since it is discontinued) would be the GEX-P5700TV
Another way is look for a tuner that outputs to RCA video and has its own remote control since you can't control it through the HU, like this alpine tuner
Edit: Just remembered, when Feb 17th 2009 comes around all Analog tuners will stop working. I would wait until companies come out with a DTV tuner