The Arduino Galileo is based on the Intel Quark SoC X1000, and should be in the store by the end of November, though the lucky attendees at Maker Faire were given one at the door yesterday. (If anyone has a spare...)
Intel plan to give away 50,000 to Universities over the next few months.
It's expected to be available in Spring 2014.
Linux everywhereBoth boards run Linux, and both can be programmed using the Arduino IDE.
The Arduino family now spans a huge range of processing power while supporting a common development environment and compatible libraries across the whole range.