Bob Meyers created a post on how to build a Clickthrough link with report builder 2.0.
Because RB 2.0 doesn’t give you automatic Clickthrough links Bob gives you a walktrough on how to create it in RB 2.0: http://blogs.msdn.com/bobmeyers/archive/2009/03/05/how-to-build-a-clickthrough-link-in-report-builder-2-0.aspx