The XBee Explorer Regulated takes care of the 3.3V regulation, signal conditioning, and basic activity indicators (Power, RSSI and DIN/DOUT activity LEDs). This makes it SO much easier to start playing with XBee!
Looking for 802.15.4 Zigbee-like device with smarts? XBee with more features? Check out Synapse modules! Small, low-power, 2.4 GHz plug-in transmitter-receiver modules, with an extended range up to three miles and power consumption as low as 2.5uA.