PrimoPDF is a free PDF creator with no ads, no nagging, and simple to use interface and installer.
Convert to PDF from any application by simply 'printing' to the PrimoPDF printer - it couldn't be easier.
Within minutes, you can create high-quality PDFs by converting from Word, Excel, PowerPoint, and virtually any other printable file type.

Requires .NET Framework.

http://www.primopdf.com/