I've been called pessimistic before, so here's my thoughts on the OP's obsession to find an app for iPhone (at least say you have Verizon and not paying ATT):

-What happens when the phone fails you? Drop it one too many times, battery dies, screen goes out...
-You must live in and ride in warm weather. I couldn't operate my old touchscreen phone while wearing gloves.
-While you're fiddling with your gizmo, what are you going to do if some suicidal squirrel decides to make a kamikaze run at your front wheel?