For info on general Visual Studio data designtime support you can checkout the SmartClientData blog.  http://blogs.msdn.com/smartclientdata While there’s a lot of content related to Smart Client scenarios, this is the team that owns the Typed DataSet designer which is utilized in Web projects as well. 

You can also checkout the VSData team blog, http://blogs.msdn.com/VSData  which owned the Server Explorer and the Database Designer designer tools.  For Orcas the VS Data team and the VB Data team have been merged to provide an even more powerfull, better together story.

Steve