Is it possible to create an irregular window with per pixel alpha so that it
blends in to the desktop at the edges? I've managed to create an irregular
from using the colour-keyed TransparentColour property, but this leaves it
with a hard aliased edge.

I've got a png background image with an alpha channel but the alpha always
comes out black.

Is what I'm trying to achieve possible, or should I just give up now?
Cheers
Ant