こんなページを読んでいました。
Microsoft Releases Silverlight 2, Already Reaching One in Four Consumers Worldwide
Get Silverlight 2
Silverlight 2 will be available for download on Tuesday, Oct. 14, at http://www.microsoft.com/silverlight. Customers already using a previous version of Silverlight will be automatically upgraded to Silverlight 2.
今はまだ Beta2 だった･･･。