On Dec 9, Microsoft released the ASP.NET 3.5 Extensions CTP Preview for Visual Studio 2008.  Scott Guthrie outlines some  ASP.NET 3.5 Extensions CTP Preview key features this preview release provides.

These include:

• ASP.NET Ajax Improvements
• ASP.NET MVC
• ASP.NET Dynamic Data Support
• ASP.NET Silverlight Support
• ADO.NET Data Services

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On November 19, 2007, Microsoft released Visual Studio 2008.  Scott Guthrie outlines some of the Visual Studio 2008 key features.

Some reasons on why you may want to upgrade.

Key VS 2008 Features

• Full tool support in VS 2008 for WF, WCF, and WPF
• Target builds for .Net 2.0, 3.0 or 3.5
• Java Script intellisense and richer Java Script debugging
• Nested ASP.Net master pages
• Rich CSS editing and layout support within the WYSIWYG designer 
• Continued support for web site and web application project models
• ASP.NET AJAX support
• ASP.NET 3.5 ListView control
• LINQ (language integrated query) support
• Intellisense code editing improvements

Key .Net 3.5 Features

• LINQ support
• ASP.NET AJAX
• New WCF Protocols (including AJAX, JSON, REST, POX, RSS, ATOM, and several new WS-* standards)
• New base class library features

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Microsoft announced on Nov 19, 2007 the availability of Visual Studio 2008.  It also made available to the public a free version of the developer tools.  Check out the following links to obtain your free copy of these tools.

• Visual Basic 2008 Express Edition
• Visual C# 2008 Express Edition
• Visual C++ 2008 Express Edition
• Visual Web Developer 2008 Express Edition
• Popfly
• SQL Server Express
• SQL Server Compact Edition

The Visual Web Developer version includes a significantly improved HTML web designer also used in Visual Studio 2008 and Microsoft Expression Web.