Check this out -- apparently Apple have just filed a patent for bike computer software for the iPhone -- cadence, speed, HRM, altitude, incline, decline, GPS, and messaging etc....
could be interesting, although I guess an iPhone would make a pretty big head unit.
http://www.patentlyapple.com/patently-apple/2010/08/apple-introduces-us-to-the-smart-bike.html
could be interesting, although I guess an iPhone would make a pretty big head unit.
http://www.patentlyapple.com/patently-apple/2010/08/apple-introduces-us-to-the-smart-bike.html