You probably already have a free PDF viewer (think Adobe) but here's a free PDF creator, developed and licensed by Microsoft, so plays nice with your Office applications.
"With those applications you can read PDFs, but you also want to be able to convert word-processing files into PDFs. If you are using Microsoft Word in Windows, the 2010 version has a “Save as PDF” option in the “Save as” menu. Earlier versions of Word can download a free software patch (http://www.microsoft.com/download/en/details.aspx?id=7) from Microsoft to do the same thing."
Source: Getting By Without a Computer Printer - NYTimes.com