- Turn ignition on, and than turn it off after 3 seconds
- While holding the lock button, press the unlock button 3 times
- Car should now lock itself to confirm it has worked
- Turn the ignition back on for about 10seconds to confirm you have finished programing
 
what kezz said if you meant reprogramming the locks, if you meant immobiliser, then its dealer/specialist :)
 
Can I say I had same problem. Keep, KEEP trying - it will come eventually. Follow the guides (there are a couple of ways mentioned on this site, cannot remember which finally got mine to sync) Just as I was going to give up, as if by magic, it worked again! Perseverence is the key (ahem...)