You may need to print your Microsoft Word document into a PDF file because a PDF reader is more readily available than a Microsoft Word reader. Besides there are many websites like Scribd.com where you would like to upload your PDF files in order to generate more traffic just as you may upload videos on YouTube.
You may go for an expensive PDF generator such as Adobe Acrobat or something else, but if you are simply creating text in a word processor like Microsoft Word that later on you would like to print into a PDF file there is a very nice PDF driver that you can install and use with almost every Windows program. Once you have installed CutePDF all you have to do is select it in the print window instead of your usual printer. You can install the free version for your personal use.