Intel Galileo is a Intel Pentium-based platform, which is supported by Arduino IDE. It runs Linux, and it is possible to install a PCI-Express card (most often the Intel Centrino Wi-Fi board gets installed).
It is also one of the Arduino-certified platforms. The configuration in Arduino IDE consists in installing the Intel i586 boards platform in the board manager. The firmware is uploaded though the USB CLIENT port as usual.
If you want to communicate with Linux on Galileo directly, you need the cable adapter; if you would like to solder one by yourself, the pinout is available here. Connect to the board using serial port with 115200 bps, and voilà!