Whats the best solution to play my iphone 3g through car speakers?

[boson82]

I have a tape player without a aux-in.

 

[classicsat]

Then get a aux in cable with a plug on each end to mate with each device.

 

[Ell]

You could get a cassette to jack like the Belkin cassette and stereo kit
You put the headphone jack into your iPhone and put the cassette into your tape player. Or if your car has a radio you could use and iTrip which transmits the audio from your iPhone to your car radio