FreeOCR is a totaly free Scan and OCR program it very accurate and can OCR PDF files.
Softi Free OCR is a complete scan and OCR program including the Windows compiled Tesseract free ocr engine also known as a Tesseract GUI. It includes a Windows installer and It is very simple to use and supports multi-page tiff's, Adobe PDF and fax documents as well as most image types including compressed Tiff's which the Tesseract engine on its own cannot read .It now has Twain and WIA scanning.
The Tesseract OCR PDF engine is an open source product released by Google. It was developed at Hewlett Packard Laboratories between 1985 and 1995. In 1995 it was one of the top 3 performers at the OCR accuracy contest organized by University of Nevada in Las Vegas.
Minor bug fixes to PDF rendering code (from v2.5)
PDF button - can now open and OCR scanned PDF files
Images from a scanned document can be selected and placed on the clipboard
Scans can be cropped before OCR
Added button to remove line breaks from the OCR'ed text
Fixed some bugs causing FreeOCR to crash when opening PNG's
Improved user interface