Using the Crop and Straighten Photo Command in Photoshop

Because cropping is one of the most commonly used Photoshop features, this version comes equipped with an additional cropping mechanism.

Choose File➪Automate➪Crop and Straighten Photos. Photoshop then looks for rectangular areas in your document, extracts each one into its own document, and then straightens those individual images.
The Crop and Straighten Photos command is fabulous if you want to save time by scanning multiple images initially into one document (and the command works on single images as well). This command is a real manual labor time saver, and I wholeheartedly endorse it.