The Arduino Yún is now available to buy from the Arduino store, a combination of the Arduino Leonardo with a Wifi system-on-a-chip running Linino. Based on the ATMega32u4 microcontroller and on the Atheros AR9331 running Linino, a customized version of OpenWRT, the most used Linux distribution for embedded devices.
The new Arduino IDE Version 1.5.4 has also just been released, to support the Arduino Yún, with some new features, and general bug fixes.
The new Arduino Yun