CutePDF Writer is a free (for commercial and non-commercial use) tool that lets you 'print your document as PDF'. It works in the same way as you get a printed hard copy of a web page by specifying File > Print (the browser normally picks the default printer automatically). To print as PDF, you need to specify CutePDF Writer as the printer type.
You can virtually generate PDFs with any tool that supports Print functionality by downloading and installing Ghostscript (Post Script to PDF converter, GPLGS8.15; 5.01 MB) & CutePDF Writer (Ver. 2.7; 1.54 MB)
Related links:
HOW TO mimic Google Search/GMail's “View as HTML” feature to browse PDFs/Word docs online