In the 31 October 2008 release of SQL Server 2008 Books Online, the following topics have either been added or updated. Additionally, the entire documentation set for the new Report Builder 2.0 feature has been added to Books Online.
Administering Report Builder 2.0
Designing and Implementing Reports Using Report Builder 2.0
Report Builder 2.0 F1 Help
Adding Page Breaks
Comparing Report Authoring Environments
How to: Display Advanced Mode in the Grouping Pane
Planning for Report Authoring and Report Deployment
Report Builder 2.0
Controlling Row and Column Headings
Data-Driven Subscriptions
Enabling and Disabling My Reports
Exporting to a PDF File
Site Settings Page (Report Manager)
Using Report and Group Variables Collection References in Expressions (Reporting Services)