All signs points to Silverlight 2 beta 2 coming within the week:

http://blogs.msdn.com/swiss_dpe_team/archive/2008/06/03/silverlight-2-beta-2-available-later-this-week.aspx

http://msdn.technetweb3.orcsweb.com/maximelamure/archive/2008/06/03/new-features-annonced-in-silverlight-2-beta-2.aspx

The biggest news I can find:

• "Pushing" data from Server to Silverlight:
  • this is a new duplex channel which implements a smart-pull, the client sends a request to the server but the server does not respond unless there's something to say, and the client will just happily wait on that request (Silverlight does have multi-threading). 
  • If this was implemented in AJAX we'd see the browser seems to be waiting for something (a waiting connection progress bar).
  • I guess when the client receives a response, it fires a new request to the server immediately and keep waiting for new messages.
  • Various people have chipped in that they feel this may be cleaner than working with sockets - may be they just didn't like the way sockets sound, perhaps too low level and not abstracted enough ;-)
• A tab control!
  • Still no combo drop down?
  • Or trees
• Commercial go-live license
• Controls are in the runtime now, instead of being packed with your app
  • Bigger initial plugin download but smaller file?
  • I wonder why they don't allow the missing components to be downloaded from a signed-MS redistribution package when you need it, and have Silverlight install that on-demand.  (instead of putting it in isolated storage where it can't be shared with other apps).
  • Flex solutions pack controls into the swf file and no one seems to be complaining

Edit:

• Sockets goes cross-domain