When Office 2003 was announced it included support for XML as a way of storing documents. At Comdex, Microsoft have announced that they will provide royalty free licences for the XML schemas that describe Word, Excel and InfoPath documents.
This is a royalty free license and the intellectual property remains with Microsoft. The license precludes the modification or extension of the schemas. Microsoft is not offering these schemas to a standards body. This means that the schemas are for interoperating with Office - they are not intended as generalised XML schemas for the transport of documents, spreadsheets or forms. Their intent is similar to SAP BAPI, which opened up SAP to integration with other systems but was never considered for any wider role. It would appear that Microsoft will not be offering these schemas to the standards bodies and it is probable that the standards bodies would not be particularly interested in picking them up if they were offered. If you want to be able to move documents and forms around freely then use the standard schemas and if you want to interoperate with Office use the Microsoft schemas. Given that they are both in XML basic translation from one schema to the other should not be difficult although there will be some loss of detail.
This announcement opens up a whole new set of opportunities for integrating Office into business process and we expect a spate of announcements from third parties offering adaptors and connections to Office XML. On the other hand this announcement makes little difference to wider integration space.