Not to be an alarmist but depending on the wording of the patent and the lawsuit, this could have far reaching implications far beyond Microsoft's world in Redmond, WA. There are literally hundreds of dialects based on the XML specification used in tens of thousands of applications around the world. This ruling could potentially be applied not only to Microsoft Office but to OpenOffice/NeoOffice (not only do they read Microsoft's dialect of XML their native open source document, spreadsheet, presentation formats are based on XML); AbiWord; the iWork applications; almost all open source utilities; not to mention XHTML that used by many, perhaps most, web sites.
I will be greatly surprised if either the suit or the patent stands. The XML standard is copyrighted by
W3C,
MIT's Computer Science and Artificial Intelligence Lab,
European Comsortium for Informatics and Mathematics, and
Japan's Keio University and has from the beginning been considered open source. While it is possible to patent intellectual property the long history of SGML > HTML > XML would seem to make it very difficult to prove the patent was based on independent work by i4i.