I've done a variety of things, getting progressively better results as I go. I'll link some samples of some of the setups I've used. (Note that we are always at the mercy of the sound guy, so they aren't really true apples and apples comparisons, but you can listen and see what you think)
If at all possible, I always run the audio on a seperate stand. I have used the Rode SVM on camera, and while it is the simplist and sounds pretty good, but as the others pointed out the sound will "move with the camera". Also, you'll tend to get more handling noise as.
Lately I've been happy running my Busman BSC-1's-->MixPre-->R09HR, and when I am close enough to the mic stand I'll go line out of the MixPre to the SignVideo XLRPro mounted under the camera, and then into the camera.
Here are a couple multicam recordings I've done of a friends band with different setups:
Canon HV30 and Panasonic PV-GS400's and GS500's, BSC1's as described above for audio:
http://www.youtube.com/watch?v=oAxhC5Xevsshttp://www.youtube.com/watch?v=2pyf7qEGGUU&feature=channelPanasonic PV-400's and GS500's, with 2 Rode SVM's on two camera's mixed (a little too much echo)
http://www.youtube.com/watch?v=AU2OvIHgzXg&feature=channelAnother one using Rode SVM's on camera (very very loud show!)
http://www.youtube.com/watch?v=w_7URfY3Eyk&feature=channelAnd here is a sample of my family playing, again using BSC1's MixPre R09HR. On this one I set all the cameras and the audio, hoped for the best, and went on stage to perform!
http://www.youtube.com/watch?v=JbGYuu3ga9c You can see the mic stand at 20 seconds, on the right side next to the sound guy standing up in the green shirt. Actually now that I think about it, I might have had a little bit of the SB into a MT2 mixed in, I can't remember.
And two more samples using audio from Church Audio CA-14 Omni's-->CA-9100-->R09HR, again I had to "set and forget" and go play.
http://www.youtube.com/watch?v=ytTyo38SeYE&feature=channelhttp://www.youtube.com/watch?v=8dutxEg3G4s&feature=channelAnd a last sample, using the CA-14 Omni's-->CA-9100-->R09HR + SBF-->MT2 mixed in.
http://www.youtube.com/watch?v=IZPn5YWZCmI&feature=relatedhttp://www.youtube.com/watch?v=O9uTquxcLzM