Original deal was $38 + delivery (http://www.ozbargain.com.au/node/75428) but that has expired. Thought it was worth posting again.
I have already bought one and tried it out and it's great. I originally had a Plantronics K100 but you had to turn the unit on and off manually everytime you got in and out of the car. With this Belkin unit, it turns on & off with the ignition and pairs automatically. The unit needs to plugged in to power it but the cigarette plug has a USB port on it. The music and call quality is great through FM.
If your car stereo has an AUX port without handsfree calling, then you're probably better off getting the Belkin Aircast.
If you want a cheaper one without Bluetooth (uses the headphone port on the phone), then there's this one for $28 + delivery - http://www.estore.com.au/CarAudio_Connect_FM_BLK000700.aspx#…
Took 1 week before they got stock in for my pickup last time, and i only ordered 6 hours or so after they said they had 300 units available.