Hopefully the above post provides a basic understanding of how to think about and use Lambda expressions.  When combined with the built-in standard query extension methods provided in the System.Linq namespace in "Orcas", they provide a really rich way to query and interact with any type of data while preserving full compile-time checking and intellisense. 

By taking advantage of the Expression Tree support provided with Lambdas, and the IQueryable<T> interface, framework developers building data providers can ensure that the clean code that developers write executes fast and efficiently against data sources (whether a database, XML file, in-memory object, web-service, LDAP system, etc).

Over the next few weeks I'll complete this language series covering the new core language concepts from a theoretical level, and then move on to cover some super practical examples of using them in action (especially using LINQ against databases and XML files). 

Hope this helps,

Scott