Hi MuZZy,
> I need to add a button to the Command Box (not sure if that's the correct
> word for it) of the form - to the top right corner where "Minimize",
> "Maximize" and "Close buttons" are.
The "Command Box" you are talking about is actually called the title bar of
the window, i.e. the usually blue bar that has the title of the window on
the left and the three buttons on the right.
There's simple example about how to add your custom buttons to a window's
title bar on The Code Project web site:
Adding a 'Minimize to tray'-button to a Form's caption bar:
http://www.codeproject.com/csharp/mintraybtn.asp
This is a simple example, but should get you going.
> I'm 100% sure it's possible as i've seen some apps adding this button even
> to independent forms, but i can't seem to find a solution.
Yes, it sure is possible. :-) Often it is just a matter of googling with the
correct terminology!
Oh, while I'm at it, here's a simple example if you want to customize the
system menu (or control menu) of the window as well:
Modify a Window's System Menu
http://www.developerfusion.co.uk/show/4655/
Hope this helps.

Signature
Regards,
Mr. Jani Järvinen
C# MVP
Helsinki, Finland
janij@removethis.dystopia.fi
http://www.saunalahti.fi/janij/