New in CTP16 / SQL Server 2005 Community Tech Preview (September) -- If you've spent a lot of time building the perfect model for use by Report Builder, you may want to use it as a data source for any reports you build with VS Report Designer, too.
Well, now you can. If you explore the Data Source designer in the September Community Tech Preview, you should see "Report Server Model" show up in the Type combo-box (where you select Microsoft SQL Server, OLEDB, ODBC, etc.) . After you select this value, use the Connection String text box to specify the location of your model on the report server. The connect string should be made up of two parts: the first part is the location of your server (server=http://yourserver/reportserver), then a semi-colon, and then the path to your model (datasource=/SomeFolder/SomeModelName).
Here's an example:
Add your credentials information, and you're done. If you happen to be creating the data source as the result of choosing <New Dataset> from the Dataset combo-box, leave the Query String blank...
Once you click OK, you'll get a very cool little UI which allows you to drag and drop entities of your model into a design surface. I think this is *way cool*.