BMW released a free iPhone app for motor hooligans. It records Forward g (acceleration) and Lateral g also. It's not as robust in it recording as some of the pay apps... but hey, it's free. Could be good for a little goofing around.
http://www.autoblog.com/2010/01/04/bmw-releases-free-m-power-app-for-the-iphone/ (http://www.autoblog.com/2010/01/04/bmw-releases-free-m-power-app-for-the-iphone/)
Very nice!
Wouldn't it be great if you could combine this with GPS data for track days [moto]
Too bad phone needs to be held flat.
Yeah it's far from 'perfect' but one cant' really complain on a free app. The BMW one taps out at 2000 meters of recording anyways - which won't do you much good for anything beyond a short lap.
Look up Motion X GPS - they have a 'Lite' free version and a more robust pay version. They both have logging/tracking. I've yet to try it while stuffed in my leathers though...