Check this App out! Everything you see on the video, has been done by / on the Iphone (except for the rpm and gears which require an additional OBD interface connected to the Iphone).

http://www.youtube.com/user/HarryS91.../0/i-SF7jgbE6k

Copied from the website: http://www.gps-laptimer.de/Home.html

FULLY AUTOMATED GPS-BASED LAP TIMING TOOL
✦ Automatically starts and stops lap and sector timing using triggers
✦ ‘No Touch’ operation on track
✦ Realizes accuracy better than 0.1s even with standard sensors
✦ Uses custom defined or preloaded triggers
✦ Includes a manual stop watch

POWERFUL DATA RECORDING TOOL
✦Stores all sensor data in its database for later analysis
✦Offers a broad spectrum of export formats including Google Earth™
✦Visually shows line driven and lateral acceleration
✦Analyses braking and acceleration points
✦Analyses corner and straight speeds
✦Lap to lap comparison to analyze impact of line driven TP
✦Histogram view on speed, lineal+lateral acceleration, and height

Has anyone on here used this App? It looks pretty damn cool for $16.99

 

Couple people have used it, I used it myself for the first time in June. Only difficult thing is finding a good attachment for the iPhone so you don't have to take it out of various cases to mount it. Upside is it's pretty cool for the money. Downside is it's not very accurate but it's close enough for decent reviews. Still won't replace a traqmate or others.

 

it was very very accurate for us at hallet last race. all the top guys in TTA were using it, and they were all within a .1s of the recorded time. in one case, the official time was quite a bit slower then his Harrys time, and we reviewed it on his in car and the official time was wrong (although, they don't consider video or harrys time to be official so it didn't really matter)