Free gDoc Creator™
– the only enterprise-resilient PDF and XPS creator and viewer available for free!

"Create, view and print your enterprise-quality PDF files using gDoc Creator, the easiest way to convert documents from Word, Excel, and PowerPoint into PDF or XPS! And gDoc Creator includes PDF to Word conversion too!."
Unlike other free PDF conversion tools you can create your PDF files instantly in one click from your MS Office application toolbar (Office 2003 and 2007).
Plus, your free gDoc Creator includes an evaluation copy of gDoc Fusion to give you free PDF and XPS viewing. You’ll also see how easy it is to merge and join PDF documents together."

Recommended Configuration

1.3GHz or faster processor
Microsoft® Windows XP SP2 or SP3 (32-bit and 64-bit);
Windows Vista® SP1 (32-bit and 64-bit);
Windows 7 (32-bit and 64-bit);
512MB of RAM (1GB recommended)
250MB of available hard-disk space
1,024x768 screen resolution

Others info and download (120 Mb !) :
http://www.globalgraphics.com/en/gdoc/free-creator
http://www.globalgraphics.com/en/gdoc/creator