Garmin Forerunner is a small GPS with specialized features for runners and bicyclists. It's designed to be worn on your wrist or arm.
While you run, Forerunner provides pace, distance and other data computed from GPS measurements. It also keeps a run history with summarized data for each of your past runs. Most models can upload saved data to a PC.
Forerunner 301 and Forerunner 305 include a heart rate monitor.
Although it was designed primarily for running, Forerunner also works well for bicycling. It's display can be set to show either speed or pace, but it lacks a sensor for cadence data. Riders who want cadence data should look at Garmin Edge 305.