I had Google maps running on my iPhone the other night and the voice guidance was playing through the car speakers. I have bluetooth ULF but that's all I have.
Every time there was a new prompt, the cars satnav screen would change to telephone then back to the map.

Weird!

The ULF will turn your car into a really expensive Bluetooth headset, as far as you iphone is concerned anyway.

I would imagine that anything on the phone that is set to use a headset will play through the car.

Not tried it on mine as I tend to use the sat Nav in the car. 2011 Range Rover Vogue SE 4.4 TDV8

Previous cars :
2003 Range Rover Vogue TD6
1999 Discovery Td5 ES
1995 BMW M5 3.8 6 speed
1992 Range Rover 3.9 Efi Vogue
1992 BMW M5 3.8
1988 BMW 735i SE
1989 Ford Sierra XR4x4 2.9i
1981 Ford Fiesta Supersport

Shame it won't play music!

Yea, not sure how that works.

The phone definately sees the car as a headset...... Though I'd imagine the Apple side of things is even more locked down than the ULF ! 2011 Range Rover Vogue SE 4.4 TDV8

Previous cars :
2003 Range Rover Vogue TD6
1999 Discovery Td5 ES
1995 BMW M5 3.8 6 speed
1992 Range Rover 3.9 Efi Vogue
1992 BMW M5 3.8
1988 BMW 735i SE
1989 Ford Sierra XR4x4 2.9i
1981 Ford Fiesta Supersport