Tesseract - Tesseract is an optical character recognition engine for various operating systems
Onlineocr.net - Free Online OCR service allows you to convert PDF document to MS Word file, scanned images to editable text formats and extract text from JPEG/TIFF/BMP files
GOCR - GOCR homepage. GOCR is an OCR (Optical Character Recognition) program, developed under the GNU Public License.
Prizmo - Prizmo is a scanning application for Mac with Optical Character Recognition (OCR) in over 40 languages with powerful editing capability, text-to-speech, and iCloud support.
TextGrabber - Office & Productivity
CopyFish - Copy, paste and translate text from any image, video or PDF.