A few of us went to a Microsoft presentation at Cambridge University last night on ASP.NET and AJAX (aka Atlas). It is currently on Beta 2 and should ship by the end of the year.
The presenter recommended taking a look at Scott Guthrie's Blog on ASP.NET and .NET:
There is a lot of interesting stuff there.
Scott is the General Manager within the Microsoft Developer Division. He runs the development teams that build the following products/technologies: