This is yet another experiment with my Garmin GPS Unit, the Geko 301. Try going into full screen mode (press F11 in IE, and make all the toolbars go away), then click on the "Follow route" button above.

The map to the left shows the track log when biking on the easiest part of the Don Valley network of mountain biking trails. I just bought a Bike mount for my Geko at the Mountain Equipment Coop (MEC), but unfortunately it wasn't the right one. I still managed to rig it up, but I didn't want too bumpy a ride until I get the real bike mount.

I was pretty impressed with the results -- compared to having the gps unit in the back pocket of my shirt. When I had the GPS unit in the pocket, it kept getting a weak GPS signal, and the track points were useless. But with the bike mount, it's mostly pretty good. This particular track is on the way back; on the way there, it screwed up once.

It'd be nice to try an external antenna to see if that helps, but unfortunately it doesn't seem like the Geko unit supports external antennae.

You can find some good GPS Units mountain biking trails, maps, bikes on the web