Connecting tv as external monitor to samsung

Hello, I would like to connect my TV to my Samsung Netbook to watch BBC iPlayer and other stuff on a big screen.

As my TV has a VGA socket, I bought a cable with VGA plugs at each end, since my netbook has the VGA socket too.

However having done that, I am stumped. I tried tweaking the properties when you right click on the desktop, but that did not work.

Is there an idiot's guide to how to do this? I am sure that it does work, it is just that I cannot seem to do it and there seems to be dozens of people with the same problem.

I am running Windows XP home edition on this netbook and XP Professional on another. I could not get that one to work either. I am using Google Chrome on my Netbook and Sea Monkey on the other.

Many thanks