Convertii (www.convertii.com) is a free online service that lets you convert a PDF file to an editable MS Word document. It's better than many such converters I've tried, in that the results it produces are pretty good. It's totally free to use, and you can even do 3 conversions without having to register. After that, you'll need to register (it's still free) to carry on using the service.
To convert a file, just drag it into the correct place on the web site, or upload from your hard disk. Supply an email address, and the converted file (or at least a download link to it) will be emailed to you as soon as the conversion is done.
While all this sounds pretty good, Convertii has an extra trick up its sleeve. Link the service to your Dropbox account, and then you can initiate a conversion simply by dropping the PDF file into the correct place in your Dropbox. Convertii will automatically pick it up, convert it, and put the Word document back in Dropbox for you. Neat!
Full details of how to do it are on the FAQ page at http://www.convertii.com/blog/faq