Mike:
I have the small Goal0, which I brought onto Whitney back in March to charge my iPhone4 with (I was using my phone in lieu of a camera, and updating status on FB). I carried the solar panels on my pack while we climbed, and several hours in the sun was enough to charge my phone at night. Since the weather forecast wasn't favorable, I brought extra batteries (charged at home) for backup.
Here's what it looks like on my pack (we were taking a lunch breat at UBSL):
