I have been checking many sources and want to confirm this.
Kirby Wii's official name is Kirby Returns to Dreamland. Wikipedia, IGN, GameStop, etc. are using this name and have updated their information. GameFAQs has not changed to the name of Kirby Wii yet, but this is probably because they are waiting to see the packaging before realizing that some kind of mistake could have been made. Comic-con's footage seems to use this title as well? I don't see it as a bad move to do it, as well, but are we waiting? If not, I will add it into the wiki unless someone else beats me to it, first.
EDIT: Oh, look at this beautiful piece of information:
"During E3 this year, most of you had heard of the new Kirby platformer for Wii, which was at the time titled Kirby Wii. At Comic-Con this year, Nintendo reps started calling it Kirby Returns to Dreamland, and that will be the final name. Kirby Returns to Dreamland will be released for Wii this fall."