Yep, quite a common problem with VW cars. Had it on my MkV Gti which the dealer fixed easily because they had just had to do it on a brand new Passat.
I get it at cold tick over (just above 1000rpm). It is caused by some cable or pipe rattling against firewall (the bit that separate's you from the engine). All the dealer has to do is secure it away from this area. 5 minute job.