That Bluetooth module is designed to work off a normal quality D.C. supply in digital logic surroundings. Keep in mind it works at 2.4 GHz where there won't be much disturbance anymore from your PIC's 10-20 MHz or whatever it is.
I would simply hook it up and use your typical 100n bypass caps on the PIC, the module etc. Only if you can /really/ identify supply related problems would you need to go further, e.g. add a small RF choke between the circuits. But only if you can measure before/after, not add it like sprinkling magic fairy dust while your problem might be, let's say, antenna related.
Nothing to do with isolation.