The Official ASP.NET Website: http://www.asp.net/. This site is the best ASP.NET information source for samples, downloads, webcasts, etc.
Scott Guthrie's ASP.NET blog site:
http://weblogs.asp.net/scottgu/ If you haven't heard of Scott Gu, then you're in for a plethora of great learning material on ASP.NET. His site is one of my favorite blogs on ASP.NET. Check out the new Model-View-Controller that will be in VS 2008, SP 1. It's a CTP as of March, 2008.
WCF SOA Virtual Managed Services Engine: http://www.codeplex.com/servicesengine. I review the MSE in the Architectural Overview, MSE Service Intermediary page, and I am impressed with this open source product from Microsoft Services. I am waiting not so patiently for the VS 2008 version, though, that should add workflows to the mix. Good work, Microsoft!
WF is Matt Winkler's forte, and he's one of the original purveyors of workflow technology for Microsoft. His website is in my IE favorites at: http://blogs.msdn.com/mwinkle/default.aspx.
AJAX: ASP.NET AJAX and the AJAX Control Toolkit are available at: http://www.asp.net/ajax/. This site includes examples and documentation on all things to create rich client web applications. Lots of how-to webcasts as well.
SOA J2EE-style: Keep up with Microsoft's competition to leverage your feedback to the evangelists. Sun and Oracle have SOA products as well, and it pays to keep up with Microsoft's competition to keep the .NET products up-to-date. If they have features that impress you, let Microsoft know.
jQuery - This is the most exciting client side addition to Visual Studio and Web programming since ASP.NET. Please check out the official website at: http://jquery.com/