You create an event inside any class, which includes a form if that is
what you wish. Any consumer referencing your class can then handle the
events that are fired by your class.

   Creating the event in C# is a two-step process: You create a delegate
with the type of the event and then you create the event itself:

    public delegate void MyEventHandler(object sender, EventArgs e);
    public event MyEventHandler MyEvent;

   Now you have to decide under which conditions you want to raise that
event. When those conditions are met in your class you raise the event by
calling it:

  if (mycondition)
  {
       if (MyEvent!=null) MyEvent(this, EventArgs.Empty);
  }

   Notice the check for a null condition. This is to avoid an error in case
no one has subscribed to the event.
   Notice also that we included two arguments, 'sender' and 'e'. This
follows the pattern that Microsoft established for all the events in the
Framework, but it is not a requirement for the event to work. You can define
events with any combination of arguments.

Did you look at http://msdn2.microsoft.com/en-us/library/ms171548.aspx
?