search the net or the newsgroup, this has been discussed numerous times

Ok first get a flashlight and, if your back is stiff, someone more
flexible. Open the front passenger door and slide the seat back. Get
on your back and with the flash light, look up under the dash, toward
your left (this would be on the door's side of the dash). You should
see a brass colored box with a wire harness and wires attached to it.
You might see a label that says "Digital Touch Entry Control Unit" or
something like that. You should also see two or three lines of code on
the label. One of the lines should begin with the letter "S". Record
the last 7 NUMBERS on that line, that's the master key number (well it
should be).

Now, wiggle out of the car and shut the door. Press the button labeled
"C"/"ST", where "C" is on the top and "ST" is on the bottom. Now enter
the seven digit master key and you should hear a constant tone sound,
during this period, enter a 5 to 7 digit entry key, this cannot match
the master key. There also  cannot be three digits in a row that use
the same button, I.E. 909xxx or something like that. After you've
entered the code, wait for the tone to stop, press "LCK"/"9|0" to lock
the doors (HAVE A KEY READY JUST IN CASE YOUR CODE DOESN'T WORK
STUPID!). Now press "C"/"ST" and enter your new code, the doors should
unlock

Al Moodie.