Raja,
I'm sorry to say, our iPhones paired beautifully with one exception.
At the dealership, we handed the salesperson my wife's 3GS and he paired it, the contacts transferred nearly instantly and when he switched to Bluetooth audio, music started playing.
Still at the dealership but no salesperson to help, my phone paired and the phone portion worked right away. However the car didn't seem willing to work with the audio. It continued to want my wife's iPhone.
When I got home I took a cable and my old generation one iPhone and plugged it into the USB port. The phone was dead, but started charging and after a bit it powered up and connected perfectly with the audio system. (There is a flaw in the way scrolling works, but more about that later.)
The one part that did not work and I'll need to spend some time researching possible problems, but my contacts would not transfer. It failed each time of the two times I tried it. I'm wondering if it isn't the way I have it organized on the iPhone. 300+ contacts in 10 groups.
So I guess I had two problems, pairing the second iPhone for Bluetooth audio and transferring my contracts.
I'll try some things this weekend. I've yet to try to pair my Nextel work phone. I'll see how that goes.
Buk