Microsoft announced today that a future version of Office 2007 (due out in early 2009) will include direct support for popular document formats including PDF. The list of supported formats will include ODF (the standardized Open Document Format), XPS (XML Paper Specification), and PDF (Portable Document Format). It doesn't look like we'll be able to open and edit PDF files - only save them. The big news is the native support for ODF, which will greatly extend the interoperability between Office documents and many other productivity suites, including Google Docs, IBM Lotus Symphony and Corel WordPerfect Office X4.
Read the full announcement here: http://www.microsoft.com/Presspass/press/2008/may08/05-21ExpandedFormatsPR.mspx