A new guide has been released that details how to offer SQL 2005 in hosting environments. More documentation will be made available shortly on SQL 2005 upsell and the versions of SQL 2005 for hosting.

The first document can be found here:

http://download.microsoft.com/download/5/0/2/502e5f64-8ccb-461b-b827-fd196e4d5f02/SQLHost.pdf