I have digged out the specifications for the Maxstream XBee RF modules, which I received as part of the "Dare To Dream Different" competition package.
Please note that there is also a Zigbee variant of these modules. The ones I received are 802.15.4 versions. I'm not currently sure of the differences, so you have to look that up yourself if you need it.
You can find the specs. and other information here:
1. XBee XB24-AWI-001 802.15.4 module product manual.
2. XBee XBIB-U-DEV development board diagram.
3. USB driver for Windows (for the development board)