The Microsoft .NET Framework 3.0 (formerly WinFX), is the new managed code programming model for Windows.
It combines the power of the .NET Framework 2.0 with four new technologies:
Windows Presentation Foundation (WPF)
Windows Communication Foundation (WCF)
Windows Workflow Foundation (WF)
Windows CardSpace (WCS, formerly 「InfoCard」)
For more info visit Microsoft's .NET Framework 3.0 Community: NetFx3, Download