If you want to start learning about .NET 3.5 Enhancements, there is a free training kit available from Microsoft that you can download to learn these cool new features :
  • ADO.NET Data Services
  • ADO.NET Entity Framework
  • ASP.NET AJAX History
  • ASP.NET Dynamic Data
  • ASP.NET MVC
  • ASP.NET Silverlight controls
Also to check these MIX 08 Videos will show you some of the features :
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