Microsoft is working on the next round of certification exams for SQL Server 2012. So now is the best time to learn about 2012. The best resources to use for preparing for the exams should all come MSDN.
The first is product documentation for 2012
Additionally, expect to see material from the Technical Articles from the last 2 versions of SQL Server as well.
The last resource that I would recommend is the The SQL Server Developer Training Kit. It has examples of all the new features and you can play around with them. Just download the kit and skip the dependencies
Make sure that you also review the following topics even though they are not directly related to Business Intelligence:
SQL Server 2012 AlwaysOn: Multisite Failover Cluster Instance: SQL Server Failover Clustering, which includes support for both local and multisite failover configurations, is part of the SQL Server 2012 AlwaysOn implementation suite, designed to provide high availability and disaster recovery for SQL Server. The multisite failover clustering technology has been enhanced significantly in SQL Server 2012. The multisite failover cluster architecture, enhancements in SQL Server 2012 to the technology, and some best practices to help with deployment of the technology are the primary focus of this paper.
SQL Server 2012 AlwaysOn High Availability and Disaster Recovery Design Patterns: SQL Server 2012 AlwaysOn provides flexible design choices for selecting an appropriate high availability and disaster recovery solution for your application. SQL Server AlwaysOn was developed for applications that require high uptime, need protection against failures within a data center (high availability) and adequate redundancy against data center failures (disaster recovery).