The Windows Server Performance Team has published part 2 of troubleshooting memory issues.
This one covers excessive paging and memory bottlenecks. I like how when they list the performance counters, they give some real meat to them. For instance, there is a calculation to determine whether or not pages/sec compared to disk activity indicates a real issue or not. There is also a proviso on evalulating available bytes with respect to IIS 6, Exchange, and SQL Server, given that those three manage their memory. Definitely a must read if you're responsible for system performance.