In my earlier post found here on Visual Basic 9.0 Technology preview, I spoke a little bit about the LINQ technology. I received an email asking for more details about LINQ and specifically, if it was tied to VB. The answer to the second question (tied to VB) is NO; it is a framework feature that will be available to the other languages as well.
As to what LINQ is in more detail: LINQ is essentially a feature that will be in upcoming versions of .NET that will integrate query syntax into the framework and into the IDE (syntax checking, IntelisSense, etc.). It will sit (as currently described) in the System.Query namespace and will do many (if not all) of the things that we do with ADO.NET for SQL (called DLINQ) and XPath /XQuery for XML. As it is currently described, it does not replace ADO.NET/XPath/XQuery as much as it will be another option going forward.
Rather than writing a two page blog entry, I will refer those who are interested in learning more about it to the following link, where you will find a great backgrounder on the subject as given by Don Box: http://msdn.microsoft.com/netframework/future/linq/default.aspx?pull=/library/en-us/dndotnet/html/linqprojectovw.asp