G.H. had once asked about the feasibility of using cell phones in an AM project. Well, there's an Open source free cell phone platform about to hit the market called open moko which looks promising

http://www.openmoko.com/about-index.html

There is also a hardware development kit to create your own GPRS/EDGE networks.

http://www.linuxdevices.com/news/NS5947466557.html

For those of you more familiar with the MAX/MSP/Jitter and that thing calle d the iphone it looks like the flood gates are about to spill open as a number of artist have figured out how to integate the two as well as other softwaare in to some neat projects.

http://www.iamas.ac.jp/~aka/i-phone/

http://createdigitalmotion.com/2007/07/16/akaiphone-iphone-to-maxmsp-and-jitter-bridge/