At the Garmin booth, they had GPS units in every imaginable shape and size. This is the smallest GPS that I saw:
It has been configured primarily for athletes, to provide pace information and a "virtual trainer" that helps you meet your fitness goals. But it also contains all the normal functions that you expect from a GPS receiver.
Over at the Timex booth, they were doing something similar with the Bodylink system:
Timex describes the Bodylink system as "a network of up to 4 devices worn on the body that act together as a single information and sport monitoring system." There is a GPS unit, a heart sensor, a data recorder and, of course, a watch. The data recorder records information from the heart sensor and the GPS, and you can dump the data to your computer to analyze it when you get home.