I2C information

Arduino Wire library (I2C main page)

I2C Tutorial by Sparkfun

I2C Primer

I2C Crashcourse "What could go wrong?"

An Introduction to I2C over long wires

I2C ports

Arduino Pro Mini: A4 (SDA), A5 (SCL)

Arduino Mega: 20 (SDA), 21 (SCL)

Master Reader/Slave Sender

see Arduino page