One of the most powerful features of Microsoft Office Excel 2003 is one you can't really see: support for user-defined XML schemas. In plain English, that means you can add XML schemas (a schema is just a structure) and data to your workbooks, regardless of where the XML originated. Excel automates most of the processes for you. All you need to do is open the file and decide how you want to use the data.

http://www.liquid-technologies.com/xml.aspx