A-PDF Deskew provides a quick way to correct the skew scanned image in Acrobat PDF documents or TIFF files directly. It detects tilt images and straightens them automatically. A-PDF Deskew"s features include processing a batch of PDF/TIFF files, even working with password protected files; filtering small images which may be a logo or else; and dealing out some page only to speed the processing. A-PDF Deskew does NOT require Adobe Acrobat, and produces documents compatible with Adobe Acrobat Reader Version 5 and above. Please note: A-PDF Deskew works only with the scanned text-print image. Other image such a picture or photo may be caused error.
Source: http://www.a-pdf.com/deskew