If you are planning on virtualizing SQL 2008 then this is a must read.

Basically this change is to the number of instances you are allowed.

http://virtualization.info/en/news/2010/05/microsoft-changes-sql-server-virtualization-licensing.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+Virtualization_info+%28virtualization.info%29