The Destroyed Room (Hyperion Essbase and Reporting Services White Paper)
One of the new Reporting Services features of SQL Server 2005 Service Pack 2 is integration with the Hyperion Essbase 9.3. Similar to building reports on SQL Server Analysis Services or SAP NetWeaver BI, this integration includes a new .NET data extension and a new query designer for Report Designer. If you are interested in how this works, you can take a look at this newly published white paper.
By the way, you also can download the final CTP for SP2 to give this feature (along with the new SharePoint intergation) a try.