Here’s an article describing some use of Valve’s multi-core strategy for their engine. Obviously lacking enough technical depth… but the one interesting tidbit is that the short-term multi-core optimizations will be added in with the release of Episode 2. That’ll be interesting to see how effecient they are:
Valve Hardware Day: Multi-Core CPUs
Here is one that looks to be a bit more in depth. At the least it has the valve slides in it.
http://anandtech.com/tradeshows/showdoc.aspx?i=2868&p=1