Has anyone tried using a GPS datalogger, the type used to Geotag photographs? These are tiny GPS devices that would easily fit in a pocket. It would not give you real time feedback while running, but should be able map your run and give you speed data after you download data to your computer. Most seem to use Google Maps or Earth to map data.
These are quite inexpensive, and seem like they could be a nice option when what you mostly want to do is know distance. I'm curious if anyone here has used these.
Thanks