Im looking for an alternative to the fm stereo adapter for playing my iphone music.

basically is there anything out there that lets you play music via the 3.5" audio jacks on the car and iphone?

I found this
SOUNDGATE® PDCBLPAK iPOD iPHONE CORE SYSTEM MP3 CAR KIT on eBay.ca (item 200504510117 end time 02-Sep-10 17:56:21 EDT)

but it looks cheap. Anyone ever try something like this? or know of any better brands?