NewOCR.com is a free online OCR (Optical Character Recognition) service. NewOCR.com can analyze the text in any image file that you upload, and then convert the text from the image into text that you can easily edit on your computer.
Unlimited uploads, no registration, layout analysis (multi-column text recognition), 29 languages support, image files (JPEG, PNG, GIF, BMP, multipage TIFF) up to 5 MB, multipage PDF documents up to 20 MB are all supported. Give this a try when you get one of those PDF files that simply won't open.
Click this link to scan PDF documents with http://www.newocr.com.