This weekend I have been tinker with SNMP in Ops Mgr 2007. It is fairly simple to create performance views and alerts based on SNMP traps. This is a great way to take control and get a overview of network devices like for example switches. You can create both alerts and performance views based on SNMP. If you are not sure which OID to build your monitor and rules on, you can use a tool named AdRem SNMP Manager. It includes a number of functions to handle SNMP, download a evaluation copy here. Getif is a free multi-functional Windows GUI based Network Tool that I also recommend when working with SNMP, link.