Yes, there will be a Silverlight Webpart in Sharepoint 2010.

This is announced there : http://sharepoint.microsoft.com/2010/Sneak_Peek/Pages/default.aspx

By the way, a lot of other Sharepoint 2010 stuffs are previewed there. The root site is : http://sharepoint.microsoft.com/2010/Sneak_Peek/Pages/default.aspx

I don't see any big revolution in this small preview (*the day after* the biggest revolution is in the Sharepoint Object Model available in Silverlight... See a later post!) on the sneak peek site but wait and see…

See you later!