Just a quick heads up on a running dj app for those who own Android phones.
It sounds very interesting. It can detect the BPM of songs on your phone, and then while you're working out it detects your SPM using the phone's accelerometers (the same way a pedometer app works). Then it plays the songs whose BPM match your current SPM. I have an iPhone so can't test this, but I have been seriously thinking of getting an Android phone and if I do I'll definitely have a closer look. The reviews look quite mixed, either it works and people love it or it just doesn't work at all. Just one final thought, in a way its doing things the wrong way round, its matching music to the SPM when what I want use music to help me keep SPM in a target range. Still I am very interested and think anything that takes SPM this seriously is worth some attention!