Heyyo,
Heh, I myself was thinking under the lines of 7zip. It's freeware, but hey Whistler, it's distributed under the "
GNU LGPL," licence.
I've seen a kickass installer already made with it: Far Cry Coop, it's sweet, the screenshots change themselves. Only 1 downside to it, it forces you to install 7zip when you wanna install any auto installers made with 7zip... so I'll try the one you suggested there whistler.