ABBYY FineReader is a widely used, well-documented commercial product for text recognition in images. Read more
OmniPage is a robust optical character recognition (OCR) application available from Nuance Communications. It convers over 120 of languages, including Cyrillic, Chinese, Greek, Japanese and Korean. It is compatible with multiple output formats, including Amazon® Kindle®, PDF, Microsoft® Word, Corel®, HTML and WordPerfect®. It can be used for various purposes, e.g. OCR, ICR, OMR, barcode. Read more.
Tesseract is probably the most widely used open source OCR application. Read more.