Anyone doing this? How does it work? Steering wheel controls work?

 

It would be really helpful if you gave us more info on your car like model, year, options etc as these can make a very big difference in the way it works.

But in the mean time I will tell you the following.

As long as the phone will support the memory card being used as a "Mass Storage Device" and only has one (1) memory card then you should be fine. The steering wheel controls should give you next track last track and volume. All other finding of music will have to be from the display controls.

More to come once we know the year model and options

 

It isn't possible. Windows Phone 7 doesn't support connection as a USB storage device. This may change with Windows Phone 8, but it isn't possible on the current phones.