Programová registrace DLL
private void RegisterForList
   (string site, string web, string listname,
    string assembly, string class) {
   SPSite site = new SPSite(site);
   SPWeb web = site.OpenWeb(web);
   SPList list = web.Lists[listname];
   list.EventReceivers.Add
          (SPEventReceiverType.ItemDeleting, assembly, class);

   list.EventReceivers.Add
          (SPEventReceiverType.ItemDeleted, assembly, class);
} 
Instructor Notes
It is pretty easy to create a small application that allows you to associate an event handler with an existing list, library, content type.

Explain that in the OM, you have a collection of event receivers developers can manage. The information needed for the registration is the full strong name of the assembly and then the class handling the event.