Hi,
Start by taking a look in the PBP3 installation folder. There's sub-folder called EXAMPLES\GENERAL PBP.
The file shift.pbp demonstrates how to use the SHIFTIN/SHIFTOUT commands and the files spimast.pbp and spislave.pbp demonstrates how to use the SSP/MSSP module in the PIC to do SPI at the hardware level.

The PBP manual covers the use of SHIFTIN/SHIFTOUT and there should be plenty of example code around the forum. Probably not exactly the code you need but plenty to get ideas from. If you get stuck post specific questions and you'll most likely get plenty of help.

With that said, if you're new to PBP then perhaps getting up to speed by interfacing a simple shiftregister or something as a start might be a good idea.

/Henrik.