[theFREAKnasty82]

This is taken from page 20 out of the owner's manual:

1. With the vehicle in Park, turn the Ignition switch to the ON position.

2. Using a previously programmed transmitter, press the Unlock button on the transmitter. Continue to hold the Unlock button, wait at least 4 but no longer than 10 seconds, then press and hold the Panic button for at least one second. Release both buttons simultaneously. You will hear a chime to signal that you can proceed with programming the new transmitter.

3. Press and release the Lock and Unlock buttons simultaneously, followed by the press and release of ANY button on each new transmitter to be programmed as well as the previously programmed transmitter. You will hear a chime when a transmitter has been successfully programmed. You will have 30 seconds to finish programming all the new transmitters. A chime will sound when the 30 seconds is over or the ignition switch is turned to the Lock position.