Microsoft .NET Framework 3.0 Redistributable Package
Microsoft .NET Framework 3.0 is the new managed code programming model for Windows.

Visual Studio 2005 extensions for .NET Framework 3.0 (Windows Workflow Foundation)
Provides developers with Visual Studio 2005 support for building workflow-enabled applications using Windows Workflow Foundation. This is a fully-supported add-on to Visual Studio 2005.

Visual Studio 2005 extensions for .NET Framework 3.0 (WCF & WPF), November 2006 CTP
Provides developers with Visual Studio 2005 support for building Windows Communication Foundation (WCF) and Windows Presentation Foundation (WPF) enabled applications. This is an un-supported add-on to Visual Studio 2005, but you may find assistance in the MSDN Forums.

Windows SDK for Windows Vista
Web download that includes documentation, samples, and tools designed to help you develop Windows applications and libraries using both Win32® and .NET Framework 3.0 technologies targeting Windows Vista. (ISO download option)

Microsoft Visual Studio 2005 Tools for the 2007 Microsoft Office System
Provides developers with Visual Studio 2005 support to build applications targeting the 2007 Office system. This is a fully-supported add-on to Visual Studio 2005.

Visual Studio 2005 extensions for Windows SharePoint Services 3.0, November 2006 CTP
Provides developers with Visual Studio 2005 support to improve their productivity when developing for SharePoint. This is an un-supported add-on to Visual Studio 2005, but you may find assistance in the MSDN Forums.

ASP.NET AJAX Downloads
With ASP.NET AJAX, developers can quickly create pages with rich, responsive UI and more efficient client-server communication. The ASP.NET AJAX Beta consists of three interrelated downloads. In addition, you'll find related downloads, such as the Microsoft AJAX Library for non-Windows platform development, sample applications and older versions of ASP.NET AJAX.