Edit:
This is exactly the program I've been looking for! Its got tons of tools for editing photos, like the "Magic Wand" tool which can be used to cut out certain objects from their surroundings, like black/white backgrounds.
Picture with white background:
Picture After background has been removed:
Resized and used as icon in RocketDock:
You can even add transparency to layers via slider
for a more see-through look.
Added Transparency:
Used as icon in RocketDock:
I've also used this on more detailed backgrounds and the results are just wonderful.
This program is open source (in other words FREE) and has tons of awesome plugins that further enhance this program.
Well, here's the latest version: Paint.Net
And here's the icing on the cake: Plugins
I hope everyone likes it.