Silverlight 2 beta 1 is out and available for download. It certainly is an amazing option for developing smart and rich internet applications (RIA). To me the best part is support for .net programming in a corss-browser / cross-platform environment. It truly makes the WPF-everywhere mantra come to live.
For more details please check out Scott Gu's blog here http://weblogs.asp.net/scottgu/archive/2008/02/22/first-look-at-silverlight-2.aspx