I just joined the 20/20 program at the proclub in order to get myself into shape, and as part of my workouts I've taken up running which - shockingly - I am enjoying. I still suck at it and can't run for long at a time but after two weeks I can tell I'm already getting better, and boy is it great exercise.
One thing I've found very motivating is the few songs on my zune that match the pace of my feet perfectly - Avril Lavigne's "Girlfriend" for example. When that song is playing, I all of a sudden have a much easier time running.
I've been browsing the zune marketplace looking for more good songs for running and wishing that there was an attribute on the songs that represented the speed of beats... and then I found http://www.jogtunes.com which does exactly that! Hooked up to iTunes (unfortunately for me), but at least it helps me find the right songs. Super super cool app.