MSDN Library - A resource for users of .NET and includes sample code, documentation, technical articles, and reference guides.
ASP.net - Home of the .NET framework with news and starter lessons.
ASPTheme.net - Web themes for your ASP .NET projects.
Channel9 - Wikis, forums, podcasts and more related to all the Microsoft tools, especially .NET.
CodePlex.com - is Microsoft's open source project hosting web site. Start a new project, join an existing one, or download software created by the community
CodeProject.com - A resource for articles and tutorials on Visual Basic and .NET.
4GuysFomRolla.com - A rich site of articles and tutorials on using .NET.
Coding4Fun.com - A Microsoft site for detailing how to use .NET with other other tools to code for Windows, the web, gaming, and hardware.
DotNetJunkies.com - Features Quickstart guides and forums.
DotNetNuke.com - An open source web framework for enterprise class web development.
DotNetRocks.com - It’s not every programming language that gets a talk radio show dedicated to it.
GotDotNet.com - A user community for .NET developers that also features code sharing.
LearnVisualStudio.net - A large selection of video tutorials to get you going with .NET.
Lutz Roeder’s Programming .NET - Offers several tools for .NET such as Reflector and Resourcer.
MbUnit.com - A unit test framework for .NET, includes advanced features to test all aspects of your project.
Mono-Project.com - An open development project that lets you run .NET on Linux, Solaris, Mac OS X, Windows, and Unix.
NAnt - A free .NET build tool.
NDepend.com - A tool built with the idea of controlling complex .NET coding, includes online demos.
NDoc - Generates class library documentation for your projects built in .NET.
NUnit.org - A unit-testing framework for all iterations of the .NET language.
ReSharper - An add-in to Visual Studio that adds in unit testing, refactoring, and more.
Snippet Compiler - A program that allows you to run small pieces of .NET code without having to build an entire Visual Studio project for it.
TestDriven.net - Adds unit testing to Visual Studio and makes it as easy as a one click.
The Regulator - A free tester for regular expressions.
TheServerSide.net - Specializing inserver side development of enterprise level projects using .NET.
W3Schhols - Features a collection of tutorials and code snippets for your use.
DotNetUrls Microsoft .NET Resource Center
CodeBetter.com - ( codebetter.com) a collection of a blogs from a group of TDD/agile development guys.
EggHeadCafe - (www.eggheadcafe.com) a quality resource for .net articles.
SubSonic ( subsonicproject.com) is the open source project featuring some of the best things of Rails but in asp.net (migrations are on the way as well as a slew of other features).
http://developer.yahoo.com/dotnet/ is your source for information about using the .NET Framework with Yahoo! Web Services and APIs.
http://msmvps.com/The Ultimate Destination for Blogs by Current and Former Microsoft Most Valuable Professionals.
DOTNET.THATSCRIPTS.COM Small Business Starter Kit, Starter Kits and Source Projects
http://www.vclcomponents.com/ VCL Components - Components, Scripts, Source Code