Take a wireless router-on-a-chip, and stick an Arduino Leonardo to it - that's the new Arduino YUN!
Arduino is fine on it's own, but when you want to make it talk to the "cloud" you'll find there's many, many paths to try out. The team at Arduino has streamlined this task into the the Arduino Yún.
Combine a standard Arduino Leonardo (running an ATmega32u4) with a chip (Atheros AR9331) that offers an embedded Linux router with Ethernet and WiFi ability, then shoe-horn it into a standard Arduino-sized footprint. All the communications heavy lifting is done by the Atheros chip, leaving all the standard I/O pins free to the Arduino!
It's a clever system, where you can still use the same Arduino programming environment to use the advanced internet abilities of the Yún.
Special to the Yún is the auto-discovery system, where your PC can recognize boards connected to the same network, letting you upload sketches via the network (in addition to the regular micro-USB connector).
Yún's networking features include:
Other Funky Features
Arduino Yun page