This unit retails for $99. Here you can get it for a fraction of the cost, and shipping is on me. This is the manufacturers description:
Play music from your iPhone or iPod on your cars stereo system
Charges your iPhone or iPod as you listen
Switch quickly between presets
Griffin-exclusive SmartSound Plus technology delivers clearest possible sound under real-world conditions
Flexible steel neck and interchangeable iPod model-specific cradles position your iPod perfectly within reach, never in the way
The look and functionality of a custom installation in your car without the cost or inconvenience
Compatible with: iPhone, iPhone 3G, 1st & 2nd generation iPod touch, 2nd, 3rd, and 4th generation iPod nano, and iPod classic (80/120GB).