And BTW, thanks for promoting my DIY site ;-)
There is absolutely NO need for anything cradle-like. The glory behind Bluetooth is that the phone can be in the trunk in your gym bag, on the floorboard, in your pocket, in the glovebox charging, etc.
Bluetooth is considered a WPAN (Wireless Personal Area Network) and runs on the 2.4ghz range. Therefore it is non line of sight.
See the videos at the bottom of my page to get an idea of how it works.
In addition to sync'ing your address book, it also allows you to talk to your car, and it talks back. You can give Nav directions, ask it to record up to 5 minute memos, and tell it to dial numbers. The voice recognition is amazing.
Any questions please let me know. My e-mail link is on my site. If anyone is in Texas or surrounding areas and needs help with their install I'll be happy to help.
http://www.golilm.com/DIY/Bluetooth