I'm looking at doing a 5k this year, so have downloaded the C25k app after several friends talked about how much they liked the program. Has anyone tried this app or any of the other C25k apps? What about armbands, or other means of clipping the phone to your body? Any recomendations? FWIW I'm in Minnesota, so will have cold weather gear on. Any earbud/headphone recomendations? TIA!