How to check for an event storm by using MOM 2005 Reporting
http://support.microsoft.com/?id=923103

Microsoft Operations Manager 2005 Service Pack 1 agents do not appear in the MOM Operator console and cannot communicate with the MOM Management Server
http://support.microsoft.com/Default.aspx?id=921288

How to determine which version of Microsoft Operations Manager you are running
http://support.microsoft.com/?id=923105

How to turn on TraceLevel logging in Microsoft Operations Manager 2005
http://support.microsoft.com/?id=923104

Lenny Wile has written a couple of good posts about MOM logging
http://blogs.msdn.com/glenw/