Optical character recognition (OCR)

Optical character recognition, usually abbreviated to OCR, is the mechanical or electronic translation of images of handwritten, typewritten or printed text (usually captured by a scanner) into machine-editable text.

All the open source software are based on the on the OCR tesseract engine. It doesn't have a GUI but provides one list of software using it.

VietOCR is the only one that I found which:

• simply works
• is easy to use.
• gives great result for screen shot. You have still to check the “ScreenShot Mode” from the Image menu.

For windows, you have also FreeOCR 2.6. It work well but you can't process more than one page at a time. May be it's the good way because you always need to clean the result.