Comments about Outdoor Research Sensor Dry Pocket for Smartphone:

This thing is great!
I use it to protect my iPhone while hiking, at the lake, or even when I cut grass to keep the dust out.
It has multiple attachment options so you can use it just about anywhere.

My only *small* gripe is that the interior headphone plug is just a little larger than the headphone port on my iPhone case, but many headphone plugs are like that.