listen/notify using C# and Npgsql

Hi,

I'm new to Postgresql. To try and learn and evaluate postgresql, i made an
application using Npgsql adapter for ADO.net and C#. All works fine, but
now i would like to obtain the following functionality:

when a app modifies a part of a DB, i want that another instance of my app
(running on another pc) is informed automatically.
I saw that Postgresql owns a Listen/Notify mechanism, and Triggers and that
Npgsql implements this thru
NotificationEventHandler,. Currently this works inside the same instance of
the app, but not on the remote pc.

Someone can help or gives a link to a sample?

thanks in advance