I just noticed that Giveawayoftheday are offering a free PDF to text OCR convertor today. Note you have to download and install it within the next 24 hours or so. The description is:-
PDF OCR is based on OCR technology to convert scanned PDF paper books and documents into editable electronic text files fast and easily. PDF OCR has a build-in text editor which allows you to edit ocr result text without MS Word.
PDF OCR also supports batch mode to OCR all pages of pdf file to text at a time. PDF OCR has a Scanned Image To PDF Converter, which means you can create your own scanned PDF books.
http://www.giveawayoftheday.com/
I have not tried it but will be downloading it when I get home from work.
HTH