could be an endless amount of things causing that.. flywheel can warp giving a vibration/judder at idle, but then so could a half-knackered engine mount.. but its more likely electrical, temp sender, air mass meter, plugs/leads etc etc .. if there's a vw specialist near you ask them to check for faults (dont go to the dealership they sting you £70 inspection fee) and they can narrow it right down, or at least eliminate a lot of the possibilities.
might be worth your while doing a search on here too, use keywords like "juddering" and see if any problems we've solved in the past have similar symptoms to you.
oh and welcome to the site
