It's an interesting idea but I think I'd rather take a few minutes to install the free pdfcreator from http://www.pdfforge.org/ However I've had reason to use google docs recently and it's a valuable addon when you are out and about.
Sarah, does the free one you mention retain hyperlinks when you create a document? I know that PrimoPDF (in fact, every free converter I found when I ran into this) does not. It was that problem that lead me to Google Docs and their PDF capabilities a couple of weeks ago (since the links do come through properly when using them). -Michael