Does it have to be an armband? I've got one that goes round the waist, clear pocket at the front and very stretchy belt so it doesn't bounce around. I tend to put it under the bottom edge of my top if it's raining, just for some extra protection. I got mine from Up & Running : http://www.upandrunning.co.uk/tune-belt-ip2-sport-belt-for-iphone-and-smartphones-ip2
