How to build a custom iPod or iPhone cable

http://revision3.com/systm/ipodcables

How to make an Ipod charger while playing audio out.
See video on link above.

Below  is an unit that make this an easy task. Link to buy it is shown in the video.

To make an audio out:

Audio out is: pin 2 = Ground
                      pin 3 = Left channel
                      Pin 4 = Right channel
The wire you connect ground for left and right together.