Development for Windows Messenger?

Hi,
I just found the kewl feature of Microsoft Alarms, that notifies me if I get
an answer to a thread in the Microsoft forum. I would like to know if there
is any possibility to develop my own tab (or register card) for the windows
messenger?

I would prefere C#, but any language (well not any, but the best known ones)
is good.

Can anyone help me on this one?

greetings

Stampede
.