One of our Premier field Engineers, Ambrose Wong, wrote a fantastic Connector Quickstart Guide that Jakob Oleksy put out on his blog. If you're interested in developing your own connectors then this is the place to start. The intro is below but to get the entire 36 page doc see http://blogs.msdn.com/jakuboleksy/archive/2008/01/09/scom-connector-quickstart-guide.aspx.
A connector is a custom service or program that allows System Center Operations Manager 2007 (SCOM) to communicate with external systems. For example, you can create a connector that sends Operations Manager alerts to an application that tracks the alerts. The application can use the connector to send an update to Operations Manager, indicating that the alert has been resolved.
You can develop a custom connector by using the Operations Manager Connector Framework (OMCF). The OMCF provides methods and types that you can use to initialize and manage a connector.
To continue reading see http://blogs.msdn.com/jakuboleksy/archive/2008/01/09/scom-connector-quickstart-guide.aspx for Jakob's blog or http://blogs.msdn.com/jakuboleksy/attachment/7046052.ashx for a direct link to the doc itself.
J.C. Hornbeck | Manageability Knowledge Engineer