Straightening images in Photoshop CS 6 is slightly different than Photoshop CS 5. Actually, Adobe made it much more logical! Imagine that a company that uses logic! In the past the straighten tool was lumped into the Ruler tool, kind of weird but it worked! In Photoshop CS 6 you can find a little level in the Crop tool that will straighten and crop your image in a much more efficient way than Photoshop CS 5.
The tutorial will guide you through straightening an image, cleaning it up and sharpening it afterwards.