OpenOffice.org 2.0, a free, cross-platform, open source office suite was publicly released on 20 October 2005 and may be downloaded here:
http://download.openoffice.org/2.0.0/index.html
OpenOffice.org can import and export Microsoft Office files, and offers the option of saving files in Adobe Acrobat (PDF) format.
There is little sense in spending hundreds of dollars to purchase Microsoft Office (or thousands of dollars for a site license) when OpenOffice.org is available absolutely free with no licensing fees and will open your existing Microsoft Word, Excel, and PowerPoint files.