There are some good katmai whitepapers appearing on the the katmai site.  The list is available here http://www.microsoft.com/sql/2008/learning/whitepapers.mspx

Performance and Scale http://www.microsoft.com/sql/techinfo/whitepapers/sql_2008_perfandscale.mspx 

Manageability http://www.microsoft.com/sql/techinfo/whitepapers/sql_2008_manageability.mspx

Delivering location intelligence with spatial data http://www.microsoft.com/sql/techinfo/whitepapers/spatialdata.mspx

SQL Server 2008 Reporting Services http://www.microsoft.com/sql/techinfo/whitepapers/sql_2008_ssrs.mspx

What's new for XML in SQL Server 2008 http://www.microsoft.com/sql/techinfo/whitepapers/sql_2008_xml.mspx

Managing unstructured data http://www.microsoft.com/sql/techinfo/whitepapers/sql_2008_unstructured.mspx

Server consolidation http://www.microsoft.com/sql/techinfo/whitepapers/hosting_sql_srv_consol.mspx

Data warehousing http://www.microsoft.com/sql/techinfo/whitepapers/sql-for-datawarehousing_2008.mspx

Data Programmability http://www.microsoft.com/sql/techinfo/whitepapers/sql_2008_dp.mspx