This was actually announced yesterday, and I was planning to try it before I posted on it. Unfortunately, the download page on Foxit's website is broken.
From the press release:
Now enabling users to populate, submit and save PDF forms, and annotate PDF files at no cost, Foxit Corporation, a leader in PDF software solutions, today announced the release of Foxit Reader 4.0, the newest version of its small, fast and feature rich PDF viewer for Microsoft Windows. The Foxit Reader 4.0 is a free alternative to other Windows software applications, now including document collaboration, commenting tools, spell checking, multi-level security and multimedia support.