Some time ago we were discussing in this Forum the pros/cons of having the PIC-based HP41 emulator communicate with the outside world via a USB interface.
I suggested that Bluetooth may be better, but I was tald that its too complicated/expensive.
Well, there is an off-the-shelf module that allows serial comms over Bluetooth.
http://www.lemosint.com/scripts/bluetooth_promiesd_02.asp
The is also an article in the Circuit Cellar Magazine explaining how the PromiESD-02 module can be interfaced with PIC processors. (#171, Oct 2004, Big PICs by Fred Eady).
http://www.circuitcellar.com/magazine/
**vp