turn key from 0 to ignition 4 times in quick succession, hear a beep, hold any button on the remote for 5 seconds and your should hear another beep, that's the key programmed, if you have more than one remote press the next remote in quick succession after the first one, they hold up to 4 remotes on memory. If after turning the key you don't hear a beep then the key needs to be programmed with the ecu via cables and extra equipment. failing this disconnect battery for half and hour and repeat, failing this try the link jayeff posted. the key also has a part inside the remote which wears out over time in which case you need to replace the key.