Flutterby™! : Portable Rotary Phone

At the O'Reilly Emerging Technology Conference, watching a guy from Spark Fun Electronics give a presentation on the Portable Cellular Rotary Phone. They use a Telit GM862 board, for a hundred bucks and change you get a serial controlled GSM or GPRS or PCS module that you can interface to cheap microcontrollers, and it takes a standard SIM card.

They've even got one that looks like it'll let you pass Python across the AT command set...

If you're hacking with cell phone stuff, this looks like a reasonable way for mid-range quantities to build embedded cellular network apps.