Hi,
Just a casual thought,... Since bluetooth modules are costly,but Bluetooth USB Dongles arent (relatively),is it possible to use them(Bluetooth USB dongles) for Bluetooth comm ?
Similarly for WiFi dongles..or even for that matter,USB->Ethernet dongles??
It has been done - I'll try and find the link - but is not easy by any stretch of the imagination.
You need to use something like the USB host shield (SparkFun USB-C Host Shield - DEV-21247 - SparkFun Electronics), implement some of the USB protocol, implement some of a bluetooth stack etc. etc.
If you can get away with only using the serial port profile then there are other options:
Bluetooth Bee $23.50 could probably be made to work without an xBee.
http://www.seeedstudio.com/depot/bluetooth-bee-p-598.html
An SPP Bluetooth module $14ish could be adapted into your own circuit (with 5v -> 3.3v conversions etc.), IF you can solder better than I managed.
http://cgi.ebay.co.uk/Bluetooth-UART-RS232-serial-Converter-Module-TTL-Ship-/200511542882?pt=LH_DefaultDomain_0