The Microsoft .NET Framework 3.5 CTP is a preview release of the latest version of the .NET Framework.

Many ISV's, enterprises and Microsoft product teams are successfully building on the new features Windows Workflow Foundation (WF), Windows Communication Foundation (WCF), Windows Presentation Foundation (WPF) and Windows CardSpace in the .NET Framework 3.0.

Microsoft plans to continue to invest in the .NET Framework developer platform and in support of existing users the .NET Framework 3.5 has a minimal number of breaking changes. So that existing applications built for .NET Framework 2.0 or .NET Framework 3.0 should continue to run without requiring changes.

The .NET Framework 3.5 adds new features in several major technology areas; including:
· Deep integration of Language Integrated Query (LINQ) and data awareness
· ASP.NET AJAX for quickly creating more efficient, more interactive and highly-personalized Web experiences that work across all the most popular browsers
· New web protocol support for building WCF services including AJAX, JSON, REST, POX, RSS, ATOM and several new WS-* standards
· Full tooling support for WF, WCF and WPF including the new workflow-enabled services technology
· New classes in the base class library (BCL) for the .NET Framework 3.5 address the most common customer requests.

.NET Framework 3.5 is planned to release at the end of 2007 and will ship with Visual Studio code name "Orcas" and will also continue to be available for separate download from MSDN.

The Microsoft .NET Framework 3.0 (which is formerly known as WinFX), is the new managed code programming model for Windows. It combines the power of the .NET Framework 2.0 with new technologies for building applications that have visually compelling user experiences, seamless communication across technology boundaries, and the ability to support a wide range of business processes.

These new technologies are Windows Presentation Foundation, Windows Communication Foundation, Windows Workflow Foundation, and Windows CardSpace (formerly code named "Infocard"). Microsoft plans to ship .NET Framework 3.0 as part of the Windows Vista operating system. In addition, Microsoft is making these technologies available on Windows XP and Windows Server 2003.

.NET Framework 3.0 can be installed on any of the following systems:
· Microsoft Windows 2003 Server Service Pack 1 (SP1)
· Windows XP SP2
· Windows Vista
Windows Vista comes with .NET Framework 3.0. There is no separate installation package required. The standalone .NET Framework 3.0 packages are not supported on Vista.