NADA Mobile is an enhanced version of Mobile Safari that gives you access to the accelerometer, GPS, microphone--and can even be used to read the value of an external analog sensor attached to the device's mic input (without using a computer or a microcontroller).
Using NADA MobileTo use NADA Mobile you need to install the part that runs on the desktop and the part that runs on the iPhone/iPod Touch. The desktop part is easy--just download the latest copy from the Downloads section of this site.
Instructions for the part that runs on the iPhone/iPod Touch are included in the download. If you have a "jailbroken" device you can install the part that runs on your device using ssh and scp. You can also try to install with Cydia, but as of Jan. 2010 the Cydia repository was not working well. If you are a member of Apple's iPhone Developer Program you can build your own signed copy to run on your developer device.
More documentation can be found in the wiki