Making your IPHONE your car deck (without other deck)

Well, in your original question you stated you wanted to, +"...Have my IPHONE as my deck. No other deck to run off or anything."+

Not surprising there are no responses - that implies you want to remove your car stereo and just put the iPhone in its place. Not an easy task (you'd need an amp, among other things, and you'd be limited to online radio streams, since the iPhone does not have an AM/FM receiver).

IF your current car audio system has an audio line in (an Aux setting on the deck and a port somewhere), then all you need is the cable you refer to in your second post. At this point, I am not aware of a single cable for the iPhone 3G that does that, just separate chargers and headphone patch cords. Likely one will be released in the future, though.

It would help if you could be clearer about what you are trying to do.

This is not a car stereo forum, but to provide the cabling you're asking for simply involves purchasing a $20 car charger for your phone at the Apple Store and then buying a 3.5mm stereo cable for about $5 at radioshack. If you're set on having a single connector (only at the bottom), then disassemble a dock (which has an audio out) or modify it so that you have a solid place to insert the phone -- since you seem willing to do some electrical work on the car to get this to work, I'd go this route.

Personally, though, I would not want to direct-connect the iphone to a car amp. You have no control over the amplifier -- it would be always-on, including when you pulled the phone to leave your car. The better option is to simply purchase one of those Pioneer headunits and then using the integrated ipod adapter (one compatible with USB charging). If you want to only see the iPod, have the headunit moved to the glove box or under the passenger seat, and then only run the adapter cables to the instrument cluster, buy a horizontal mount, and just clip the phone in -- voila, "iphone" headunit!

Whatever you end up doing, good luck,
Josh