This device simply plugs into the cigarette lighter socket (no wiring) transmits your phone calls via your car radio and its under sixty quid. Very simple to install. Just pair the 2 devices (phone and Parrot) via Bluetooth then select a fairly quite FM frequency on your radio. Program the frequency on a radio button just like you would a radio station. Then set the same frequency on the Parrot (99.0 in my case). Now all the calls come via the radio. To make a call just say "phone" then a contact name and it dials. To answer a call simply press the station pre-set button or the green button on the parrot.
You can also plug an ipod/MP3 player into the side of the parrot and it will transmit the music to the radio and you can move through the songs via the buttons on the parrot. Clever stuff!
I got it from http://www.blueunplugged.com/p.aspx?p=120620 and it arrived next day.