Irregular shaped windows?

["Anibal F. Martinez Cortina" <linuxkid zeuz gmail com>]

I've been looking around for information regarding irregular shaped windows.
What I've found is either outdated or broken.
There's even one email in this list that points to using Cairo, but I'm not
entirely sure of diving into that BEFORE I ask this.
So, my question is, is there a way to draw a window wich is shaped by a
given set of points?
This is mostly seen on Windows applications, like WinDVD or such.

Regards.-