We have just released an XBee sized surface mountable board that be programmed via the Arduino IDE. It can take an SRF or Hope RFM12B. With an SRF over the air programming direct from the IDE is supported which is way cool as it means you can upgrade your wireless devices from the sofa 
It's £3.92 + VAT without a radio installed (can be used as just a micro if desired also)
http://shop.ciseco.co.uk/rf-328-bare-arduino-atmega-328-compatible-micro-board-rfu-328/
All the best
Miles