Are you referring to the "darker" blue sky near the middle of the frame? I actually happen to like the image. Is this a series of images you stitched together?
Yes, I was referring to the darker sky directly opposite the sun caused by the circular polarizer.
Brad are you using CS6? If so there is a Lens Correction feature that may help here. There are also other features that can help correct that. Give em a look.
I am assuming this was "stitched?"
Dan