I will be doing a presentation at PDC this year on Using the .NET Language Integrated Query Framework with XML Data.  The presentation is on Friday (8/16) at 10:30.  Hope to see you there!

Here is the abstract:

One of the key challenges to working with XML data has been the impedance mismatch between XML and programming languages. This session introduces future advances Microsoft is making for the "Orcas" release of Visual Studio in programming languages and frameworks to help integrate XML and queries with C# and Visual Basic. The advances include a framework for navigating, querying, and transforming XML that is both easier to use and more efficient than current XML programming techniques. This framework marries the capabilities of XPath, XQuery, and the DOM with the language integrated query framework planned for C# and Visual Basic. It is suggested that you attend "The .NET Language Integrated Query Framework: An Overview" before attending this session.

Luca is doing a talk on Using the .NET Language Integrated Framework with Relational Data and blogs about it here:  http://blogs.msdn.com/lucabol/archive/2005/07/14/438824.aspx