Is gtk skinable?

[Patrik Krizan <krizan cs uni-frankfurt de>]

Hello people,
i would like to wrote a program with gui like this: 
http://www.cs.uni-frankfurt.de/~krizan/winamp_window.jpg 
<mailto:gnome-list gnome org>
it is a winamp window. all i need is a window like on the picture with 
drawable area. Does anybody know, whether it is posible, to write such 
program with gtk?

My idea is to make the window transparent and only show the drawable 
area. Then i could paint all i need on this area. Is it possible with gtk?

thanks
patrik