Up until SQL 2008 R2, creating Reporting Services reports based on SharePoint list data has been a little tricky. There have been "techniques" and 3rd-party solutions available (http://www.bing.com/search?q=sql+reporting+services+sharepoint+list), but nothing out-of-the-box. With Report Builder 3.0, this process is much more straightforward thanks to the new “Microsoft SharePoint List” entry in Report Builder’s Data Source configuration interface.
To create a report based on SharePoint list data, simply configure a Data Source using the “Microsoft SharePoint List” entry and enter the URL of your SharePoint site as the Connection string.
Now when you create a new Dataset for the report, Report Builder will query the SharePoint site for the list metadata and present you with a nice GUI for selecting the list content that you need for your report.