Gail from the documentation team told me today that the Plan Caching whitepaper I've been working on for SQL Server 2008 is now available at: http://msdn.microsoft.com/en-us/library/ee343986.aspx
Thanks so much to my colleagues Andy Kelly, Itzik Ben-Gan and Eladio Rincion, and Microsoft team members Adam Prout, Campbell Fraser and Xin Zhang for tech-reviewing it.
It's an update of the whitepaper "Batch compilation, Recompilation and Plan Caching Issues in SQL Server 2005" by Arun Marathe, targeted at SQL Server 2008.