For all of you didn't noticed the name change of code name WPF/E, it is now Microsft Silverlight. Silverlight is a cross-browser, cross-platform plug-in for delivering the next generation of media experiences and rich interactive applications (RIAs) for the Web. Silverlight integrates with existing Web applications and, of course, almost all Web technologies you are already using like Ajax.NET Professional  or ASP.NET in common.
More blogs about Silverlight
There are a couple of blogs writing about Silverlight (