Moteino is a low cost wireless Arduino based on the Atmel ATMega328P microcontroller:

• Low cost Arduino clone fully compatible with the Arduino IDE
• The regular version includes an onboard RFM69HW transceiver and separate 1/4 wavelength monopole wire antenna
• RFM69HW is a 20dBm output power transceiver, 130mA in TX, 16mA in RX. You will need to use the setHighPower() function after the initialize() function in the RFM69 library. 
• This forum thread reveals a 1.5mile range on RFM69 using a dipole antenna at 1.2kbps!
• Low power battery power friendly
• 3.3V onboard regulator (MCP1703) provides up to 250mA, input up to 16V
• Very small size – 1.3 x0.9 inch (33mm x 23mm)
• Breadboard friendly header layout allows you to attach female/male header pins on the top or bottom and make shields for it or just use it on the breadboard for prototyping
• FTDI programming header (Programmable using the FOCA in 3.3V mode.)
• DualOptiboot bootloader for fast programming and no delay startup. Choose Arduino Uno under Tools>Boards from Arduino programming environment.
• Onboard LED on digital pin 9 (D9 / PB1) for debugging or visual indication
• New R4s comes with ENIG gold RoHs lead-free finish.

To make a wireless link you will need at least 2 Moteinos. Alternatively this is compatible with other Arduino clones that use the RFM69 transceiver.

All Moteinos come with a wire antenna cut to length to match the transceiver frequency.

Pinout

Programming guide

Click here for a more detailed guide. For an introduction to Moteino click here.

You can upload a sketch to a Moteino just like you would normally do for any Arduino. In the Arduino programming environment you need to select "Arduino Uno" under Tools>Boards.
You will need a USB-serial adapter to connect to the FTDI header.

For all Moteino related blog entries click here.
For example code and RFM69 library click here, and Github libary and examples are here.

Also check the LowPowerLab blog for updates and other projects.

Transceiver Datasheets

http://www.hoperf.com/upload/rf/RFM69W-V1.3.pdf
http://www.hoperf.com/upload/rf/RFM69HW-V1.3.pdf