An easy way to keep track of all running data- the Nike Plus app downloaded onto my iPod Nano. I set it for time or distance, choose the music I want (mostly I like a compilation of upbeat music I put together), and take off. It records how far I go, what time it took, my pace and the number of calories burned as well as where I am in my time or distance while I'm running. It's the best way to know exactly when to turn at the half way point. When I conect the iPod to my computer after I return home it uploads all data to my site on the Nike Plus website. It graphs the data for the run, the week, the month or the year so I see my progress visually. It allows for individual goal setting besides the recording.
Also, various sports figures (my favorite, Joan Benoit Samuelson, from Maine and the first American woman marathoner to win in the Olympics) give me feedback through my earphones when the run is my fastes or longest or when I reached another 250 or 500 miles. Very fun. It's a free app and keeps track of walks too- check it out. It's a great motivator.