The RFM22 is a low-cost ISM FSK transceiver module which offers communication at 433MHz ISM and adjustable output power of up to +20 dBm. What does that mean for you? It means your Arduino now has an inexpensive way to talk to other Arduinos so building point-to-point and even basic mesh networks just got a lot more attractive. Project description, more information and ordering can be found at https://www.sparkfun.com/products/11018 RFM22 Library: http://www.open.com.au/mikem/arduino/RF22/ Datasheet: http://www.sparkfun.com/datasheets/Wireless/General/RFM22.PDF Product Video: http://youtu.be/HELBcKLL0Zs?t=2m20s Quickstart Guide: http://www.sparkfun.com/rfm22shield