I2C for chip-to-chip communication

If you have several PIC microcontrollers and other I2C devices on the same PCB, the best bus to use would probably be the I2C bus. It’s a synchronous multi-master bus so the PICs can talk to each other while controlling the slave devices as well.

Here are some interesting sites on the I2C bus:

http://www.robot-electronics.co.uk/htm/using_the_i2c_bus.htm

http://www.i2c-bus.org/i2c-primer/

http://en.wikipedia.org/wiki/I%C2%B2C

http://www.esacademy.com/faq/i2c/