The title says it all, really. This lovely little thing converts any pdf to a plain text file, even the ones where you can't select the text (I'm looking at you, Brian Kopp). Great for putting them onto, for example, an iPod - I did this with my copy of Kopp's 1-60 way back pre-tbc when there were no in-game guides. And being freeware, it's completely legal to use for as long as you like without paying!
Downloading A-PDF Text Extractor... [A-PDF.com]
That's the link to the official site. Enjoy!