Well, as the title says, the Wii will only be available in one colour at launch, the standard shiny white.
This is kinda annoying because I wanted a black one. Also Wiimotes will only be available in white at launch, which could cause confusion over which Wiimote is which.
I heard their reasoning for this is that they can't make enough in each colour in time. Part of Nintendo's appeal is that they have their consoles in different colours (moreso with the handhelds), and this isn't gonna help in trying to reach out to the non-gamer.
This isn't such a big deal to me, as I could just sell my white one for a black one when it comes out (hopefully a Wii with DVD playback too, if it comes out in the UK!).
EDIT: Just realised after a quick search that most people know this anyway, this threads more detailed than the others I found.