Playing music on iPHONE in car

"I have a VW Beetle with the direct connection but when I plug in my iPhone the sound isn't coming thru the car speakers - it's coming through the iPod. How do I get it to come thru the car sound system? On a regular iPod it's ok but on the iPhone.
Help?
Thanks "

Are you using the VW "Aux" input? or the VW Ipod adaptor? if using the Aux input you'll need an adaptor to take the 3-input iPhone jack to 2-input style.
The headphone jacks on the iPod and iPhone are different, iPhone has 3 connectors (3rd one for the mic), iPod only two (L/R speakers)

opps, one advatage of the factory or aftermaket iPod adaptors is they also will charge the iPod / iPhone while your driving. With the iPhone you can even use the other features while the iPhone is playing songs over the stero. With the iPod adaptor in my GTI the stering wheel audio controls control volume & track selection and playlist selection.

Thanks - I will check out that Belkin adapter.

Yeah, this is great advice. I have a new BMW 328XI. Connecting the Belkin Mini-stereo plugs into the aux input in the armrest storage compartment and directly into the iPhone did NOT work, but your advice of using the iPhone dock worked like a charm. Just connect the cable to the dock or cradle rather than the directly into the iPhone.