Today Garmin announced their new Edge 500 Cycling GPS. Designed for performance cyclists, the GPS-enabled Edge 500 tracks speed, distance, time, GPS position, elevation, calories burned, climb and descent.
The Edge 500 also pairs wirelessly with Garmin speed/cadence sensors and features advanced heart rate-based calorie computation when used with a Garmin heart rate monitor. I have both the heart rate monitor and cadence sensor with my Garmin Forerunner 305.
Here is Garmin news release for the Edge 500.