Vista - Right-click in explorer

Dear Group,

I've created an application, which is doing some actions, on several
files in defined cataloge. My point is, to add position in ANY right-
click menu item in windows explorer on a directory item. Sample: I
open My documents, right-click on folder "blah_blah", displayed
options "Open, Explore..., Search, (...), Preferences" including my
application launcher. The problem is, how do I do it? I suppose I
should activate it while installing software - I use VS 2008.

Thank you very much for help and best regards,
Przemek M. Zawada