PDFCreator is good software. It's a simple Windows printer driver that prints to a PDF file instead of paper. There are other ways to print to PDF; I like this one because it is free and very easy to use. The underlying Ghostscript engine even produces decent quality PDF.
I create PDFs all the time when I want to give a document to someone. Everyone knows how to open a PDF attachment in email and it always renders the same no matter what software the recipient has. And emailing a PDF is much easier than printing and faxing something. Printing to PDF is also a big help when you don't have a physical printer. Last month in Oregon I checked in to a flight online, created a PDF of the boarding pass from the web page, then faxed it to myself at my hotel with a free email-to-fax gateway. Byzantine, but effective.