We use Primo PDF at work. It works really well for converting word to pdf, you just to print and instead of sending to a printer you send it to Primo. Very low overhead and free, no pop-ups etc. As for PDF to word, I didn't think there was such a thing for good reason. I always though pdf's were there because they are un-alterable, that is why people always make forms into pdf's before sending...so the end-user can alter it, sign it and reap the benefits because "it was on the form" (if that makes sense at all)