TO simplify BLueroom's schematic, you can probably chop off everything to the left and top of the PIC in the middle, leaving only the stuff to it's right, and the motor part to the bottom. In his schematic, he used an H-bridge IC rather than one of discrete components (The SN75410).
No regulator is in the circuit for the PIC so one should be added. A starting place to look at is how to use the LM7805. It's very simple, you should have no problem understanding how it's used if you take a glance at the datasheet (or the datasheet of any other linear regulator). I have no idea what those optocouplers are for on the top-right of the schematic so you can ignore those too.
Notice the H-bridge has uses the "raw" voltage (or a different voltage supply) from the PIC. The PIC uses a voltage that has been cleaned up by a regulator (not shown)