You don't mention what chip or circuit you have in mind to serve as the motor driver. Since a PIC typically outputs around 25mA on any given pin (enough for an LED, and actually a rather skookum output for a microcontroller, but nowhere near enough for a motor) you need to amplify that output signal somehow.
It can be done with discrete components... a transistor and such... but I have had very good luck using the
L293DNE with my Engineering 11 students when we build our mini sumo robots. The cool thing about using this chip is that because it is an H-drive it now makes it very easy to drive the motors both "forwards" and "backwards". You can even use it to do speed control if you set it up correctly.
That doesn't mean the L293 is necessarily the best choice for you... it is rated to 600mA and works well with the small motors in the
Tamiya Dual Motor Gearbox, but the
3953 can go higher. Other chips are also available... perhaps you have something in mind already.
Good luck with the project,
Jason