From the Mac Tricks and Tips blog I saw this interesting article, Extracting Text From PDF Files.

1. Open Automator, found in Applications > Utilities
2. In Automator drag out “Get Selected Finder Items”, then “Extract PDF Text”. I recommend changing the output option to Rich Text.
3. Save the file. Either as an application or a file.
4. Test. Drag a PDF file onto the Automator file and let it do its work, after a short time you will have a text file with the extracted text.