I2C? Any good tutorials out there?
Quite simple. First, a quick video about I2C from NXP/Phillips, who created it: http://www.youtube.com/watch?v=BcWixZcZ6JY

I2C is a data communication bus, allowing a microcontroller (or other host) to communicate with a wide variety of slave devices. It is 8 bit based, uses two wires (Data and Clock, and common Ground). It allows for addressing of the slaves, so each slave does not need an individual enable pin. It has methods for multiple hosts, and arbitration to make sure there is no corruption of communication. It is ideal for low pin count.