launcher-style icons

[Michael Rothwell <rothwell holly-springs nc us>]

I've been trying to find information on how to create launcher-style
icons -- the ones with the nifty drop shadow. It appears that the icons
themselves are .png files with alpha.

Does anyone have any pointers on how to get a panel applet to display
its icon in this manner?

If there's an FAQ or example I've overlooked, please point it out. 

Thanks,

--Michael

p.s. GDK and GTK docs seem to be 404 on the gnome website...