arduino and a cellphone

is there anyone out there who has dealt with reading information through arduino from a cellphone which has gps capabilities?
i would like to make arduino display on some wearable interface a reading of a distance…geographical distance from point A to point B measured on the cellphone.

I have been researching this too. I tried interfacing to a Nokia with the FBUS protocol, but this is a pain…
and expensive, too, as you have to buy the cell phone, the level-shifing interface cable etc. I am thinking this module may actually be the cheapest and fastest, although I haven’t tried it yet:

Sparkfun Cellular/GPS Module

Also, the development team is apparently coming out with a Bluetooth Arduino, so this might be one way connecting to a bluetooth-enabled cell phone. Not sure when it will be out.