VAG-COM is software made by www.Rosstech.com
that allows you to view and alter the cars software & view and reset error codes, just like a main dealer can. It allows various features to be enabled/disabled.
I mainly use mine to alter the advanced central locking options.
You have to connect your PC or Laptop to your car with an special cable (available on ebay for around £8).
There are other similar bits of software available, that will perform the same function.