Application capabilities

Word Word now has an XML format called WordprocessingML, which appears to preserve almost everything in the .doc format, as well as (Professional only) XSLT support and a toolkit for letting users mark up information for their own schemas.
Excel Excel builds on the SpreadsheetML format from Excel XP, which supports most Excel content except for charts and VBA. It also provides tools for creating spreadsheets which can import XML document information, making it much easier to separate data and analysis, plus VBA features for working with Web Services.
PowerPoint no XML functionality in this version.
Access Access builds on its existing XML support with updated support for W3C XML Schema and XSLT.
InfoPath InfoPath is a new entry into the Office suite, a form-building and processing toolkit that uses XML, XSLT, and a variety of other Web-like technologies.
Others Visio builds on its existing XML format with lots of SVG support. FrontPage adds a lot of tools for creating HTML-generating XSLT.