Office 2007 now lets you save any document, presentation or spreadsheet as a PDF (without having to purchase Adobe Acrobat). However, you have to download a plug-in to add this functionality.

You can download the free plugin from Microsoft at:

http://www.microsoft.com/downloads/details.aspx?FamilyId=4D951911-3E7E-4AE6-B059-A2E79ED87041&displaylang=en

After you have downloaded the plug-in, to save a file as a PDF, click the Office button and select Save As | PDF or XPS.