My video system is somewhat old technology and bulky.
I use a Viosport, Adventure Cam II that mounts with velcro on the helmet.
I carry a Canon ZR45MC DV camcorder wrapped in a towel and stuffed into a Camelbac MULE packpack.
The camera plugs into the A/V jack on the camcorder, and you set the camcorder to VCR mode. The mic is built inline with the cord that goes to the camera. One drawback to the camera is that it needs 12VDC to power the CCD. It comes with a AA battery holder that holds eight AA batteries. There's no power switch, you must remember to unplug the battery holder when you're done using it.
I have a small, waterproof, momentary contact switch that plugs into the LANC port on the camera to stop/start the recording. I route the cable down the shoulder strap, along with the drinking hose.
As far as software, I'm using Cyberlink Powerdirector to edit and output the video. I transfer the video to the computer using the Firewire interface on the camera.
I'm sure there's better software out there, but what I have works with my ancient, win2000 system and allows me to control the tape transport and capture the video using timecode.
MPEG4 codec seems to be the best output method, if you're going to put the video on the net.
And thanks for all the kind comments, everyone.