I think it is interesting to warn that this namespace is obsolete, but it would be very kind and useful to modify this page to tell that this namespace is "replaced" by Microsoft.SqlServer.Management.RegisteredServers
I discovered that when i discovered this link
http://msdn.microsoft.com/en-us/library/microsoft.sqlserver.management.registeredservers.aspx
this content is following a thread in MSDN-us Sql Server Documentation
http://forums.microsoft.com/msdn/ShowPost.aspx?PostID=4075567&SiteID=1&mode=1
I have remarked on this forum several threads about the compatibility between SMO 2005 and SMO 2008.
I understand that some namespaces have been displaced but it may provoke some problems when developers are creating SMO programs which must be compatible with the 2 versions 2005 and 2008
Anyway, i consider that the SMO documentation is bettering from the 2005 ==> 2008 documentation