I am going to put this under Mods/Hacks, but I don't know if it really falls here... Oh well.
Basically a third party vendor (XCM) has released black casing that you can use to replace the white casing on your Wii. It's like 40 US dollars, but to use it, you must take the old casing off your Wii, voiding the warranty from Nintendo.
Do you think it's worth it?
no!
personally, i think the wii looks nice white, although someone custom painted there wii black with a triforce on here which I thnk looks cool
http://youtube.com/dukkysm64