PlugIns? (#2) - Notification of zoom/map location change (#127) - Message List

Hi All, I've checked the documentation and forum but cannot find an answer: how do I recieve a notification when either the zoom level or map centre point changes? I have written a c# app and have successfully derived my Form from ICallback(s) to recieve notifications, this works well. I understand that the appropriate callbacks in ICallback(s) no longer work so I tried to intercept the OnDraw?() from ILayerEditor3 - i did this by deriving my form from ILayerEditor3 and implementing its methods however, none of my implemented methods get hit when I set a breakpoint. Is this the way I should be doing it?

Any help would be greatly appreciated,

Rob