OCR (Optical Character Recognition), is the ability to translate text from (usually scanned) documents. You usually find bundled OCR software when you buy a scanner. Once scanned, you can start cutting and pasting the text onto document publishing apps like MS Office or Pagemaker.
Google Docs now has the ability to allow you to upload a PDF file and convert this to text. I decided to try this out using a PDF file I got from Nokia about the new X8.