The LiveRider iPhone app and bike kit is meant to be the equivalent of the dashboard of your car, but on your bike.
The app lets you keep track of how far you have gone, how fast you are currently going and even lets you keep Google Maps handy in case you get lost. You might be able to do some of these features with just using Google Maps GPS, but you couldn't track your ride to the extent that LiveRider could. You can even put it in ghost mode, which is you chasing your previous rides and times, kinda like a racing game.
The kit costs $100, which includes the mount, the magnets and the adapter. The app is free, but doesn't work without the kit.
Check it out: Live Rider iphone app
Information from Bonnie's Fitware.
