Students of me know I am a big fan of Star Trek and as a consequence also of the serializing and deserializing of objects in the .NET framework. Look for example at my article discussing how you can use this technique to process InfoPath data dropped in SharePoint form libraries. Microsoft released this week a tool that can help you generating classes starting from an XSD.
The Sample Code Generator (XSDObjectGen) tool takes an XSD schema as input and generates sample code showing how to mark up C# and VB.Net classes so that when serialized with the XML serializer, the resulting XML will be valid according to the original schema.
Download it here.