Microsoft have released an add on for Microsoft Office 2007 to enable you to save files as PDF and XPS. There was already free third party solutions for saving pdfs, e.g. pdf995 but this one is officially from Microsoft.

http://www.microsoft.com/downloads/details.aspx?FamilyID=4d951911-3e7e-4ae6-b059-a2e79ed87041&DisplayLang=en