Arduino Library for XBee S2 ZigBee
SimpleZigBee is an easy-to-use Arduino library for communicating with XBee Series 2 and 2B ZigBee radios. The library implements the most popular XBee API frame types (TX, RX, AT Command, etc.) and makes it easy to add a wireless communication network to your Arduino project.
A 3 part tutorial for getting started with the SimpleZigBee library can be found at WallflowerOpen.com.