Found several good links on HTTP compression in IIS 6.0 and website optimization in general, as well as website monitoring.
Website optimization and speed in general.
– Free Website Performance Tool and Web Page Speed Analysis
– IIS 6.0 – Enhanced Compression and Consolidation
ISA and IIS compression:
– Really Getting ISA and HTTP Compression to Work Together
For Enterprise monitoring and website measure:
– Keynote – requires subscription.