As we know, ISA Server 2006 SP1 was released with some features for us Exchange guys. On this MSExchangeTeam post they published a serie of links to help the troubleshooting process using ISA 2006 SP1 and Exchange Server 2007 and also some extra information about ISA 2006 SP1.
Read more at source: http://msexchangeteam.com/archive/2008/12/08/450180.aspx