Here is a simple PIC-based GPS receiver system that I designed. The GPS module is a SiRF III with integrated antenna from SparkFun Electronics. It communicates via serial with a PIC16F84 microcontroller, which drives the LCD.

In this image all I've done so far is to decode and display the GPS NMEA output. I've since added a few buttons and can mark and recall waypoints.

Doing floating point math in PIC Basic is not easy, since it doesn't actually support floating point math. With a little more work I'll be able to have it calcuate distance and bearing to waypoints.