I am currently working on a custom MessageEncoder and XmlReader/XmlWriter for
FastInfoset.
The project is intended to be fully compliant with the final release of WCF.
It will feature a XmlReader and XmlWriter implementation for the ITU-T/ISO
standard for binary XML: Fast Infoset. This will run on the base .NET 2.0
framework. A MessageEncoder will tie this to the WCF message framework for
RESTful and SOAP web services.

For more information, please visit my blog at http://blog.beuchelt.com/ or
visit my chalk talk at TechEd 2006 (Wed, Jun 14).