My 2006 GTI has an iPod dock in the centre armrest, but it doesn't charge iPods from (I think) 2007 and later. I bought a Griffin Firewire charge converter from Amazon (currently out of stock, but more due). This is about an inch long and goes between the dock and the iPod. It makes an iPod touch too tall so the armrest doesn't close, but I simply bought a 1m extension lead and fed it through to the cupholder.
Now the iPod is easier to plug in, gets charged and works perfectly. All for just over twenty quid. Result.
