Yeah it's not a rumor, it has been pretty much confirmed since the original launch that hdmi was coming (although people thought it would be in the form of an adaptor).
The only thing that worries me is this:
Hdmi ports are a rarity on devices. Sure your hdtv has one, but that'll be taken up by your cable/sat box. Those probably don't have a hdmi-in port on them either. Same goes for dvd players ect... most just have composite.
I guess what I'm saying is you can use hdmi, which will really only improve your sound quality, or you can use component, get virtually the same picture quality and not have to have a switch box.
Somebody needs to come out with some smart hdmi "hubs".
An truely crazy rumor is that the "wii 2" could be out as early as next christmas for the same price as a wii, only with hd support.
