I'm always looking for great tools (particularly free/open source tools). Here's one called PDFCreator that allows you to create PDFs from any document that can print to a Windows printer.  Furthermore, it is free because it's an Open Source tool.  It's extremely simple to install and use. After running the installation program, PDFCreator shows up a a printer in your list of printers (see figure).

Here are a list of features directly from the PDFCreator website.

• Create PDFs from any program that is able to print
• Security: Encrypt PDFs and protect them from being opened, printed etc.
• Send generated files via eMail
• Create more than just PDFs: PNG, JPG, TIFF, BMP, PCX, PS, EPS
• AutoSave files to folders and filenames based on Tags like Username, Computername, Date, Time etc.
• Merge multiple files into one PDF
• Easy Install: Just say what you want and everything is installed
• Terminal Server: PDFCreator also runs on Terminal Servers without problems
• And the best: PDFCreator is free, even for commercial use! It is Open Source and released under the Terms of the GNU General Public License.