Difference between .NET framework 2.0 and .NET framework 3.0

Support for 64-bit is provided in 2.0 framework.
The major change between 2.0 and 3.0 is the new set of APIs: Windows Communication Foundation WCF - indigo in 2.0; Windows Presentation Foundation WPF - Avalon in 2.0; Windows workflow foundation WF and Windows Cardspace - infocard in 2.0. The support for HTTP pipelining and syndication feeds is provided in 3.5 framework.