Explore the exciting new tools in the free beta of Adobe's Photoshop Lightroom 5
Corrections for both lens and perspective distortion keep getting better. One of the best new features in the Lightroom 5 beta is the Upright Lens Correction tool. Check the boxes to Enable Profile Corrections and Remove Chromatic Aberration—the tool works best when those are turned on.
Start with Auto
Click Auto to level the horizon and fix Vertical distortion all at once. It seems to work very well automatically, but if you need to, fine-tune the fix by going to the Manual tab and adjusting its sliders.