To remove blue haze color: Duplicate image layer and run Blur Average, then invert and change layer blending mode to Overlay
Create a new merge visible layer and change the layer blending mode to Multiply to add contrast and color depth.
Change this layer to a smart object (for editing) and use the Lens correction filter to remove the vignetting.
Finally, add an adjustment layer (levels or curves) to tweak the brightness/contrast.


forum discussion: http://forums.dpreview.com/forums/read.asp?forum=1006&message=41192055&changemode=1
original image by Sunshine boy: