Hi Garry,
You can't save the file as PDF, however, you can print the plans / elevations to PDF
If you have a PDF writer installed in your computer, in TFP just use File --> print --> Your PDF writer will appear as a virtual printer in the Printers menu --> select it and customize the settings (scale, paper, etc)
If you don't have a PDF writer, there are several free apps in the web. You can visit download.com and perform a search with the keywords PDF + free
Pat