depends on which version of iphone you have. Only the 3G(s) has voice control for voice dialing, autoanswer etc. I have the 3G model and use it connected to my autocom for music and gps only.
If you have the 3G(S) I'm not sure if you can just plug the phone into the autocom with a lead or whether you need the bluetooth package. I think you can do it with just the lead, but not sure if you need a 4 ring connector lead or just a 3 ring one.
If you have a 3G only iphone you're out luck I think, although you can certainly still use it for music as I do.
Justin.