Today I found some very good ISA resources on ISAServer.org
ISA Firewall Best Practices, Tips and Tricks (Part 1)
ISA Firewall Dirty Dozen (FAQ)
ISA Server Tools
ISA Server Tools (MS)
Teaching the Boss and the Network Guys About the ISA Firewall (Part 1)
Teaching the Boss and the Network Guys About the ISA Firewall (Part 2)
Teaching the Boss and the Network Guys About the ISA Firewall (Part 3)
ISA Server 2004 Best Practice Analyzer
ISA Server 2006 Best Practice Analyzer