Rock Band for Wii Release Date Announced
According to this article, Rock Band will be available for the Wii on June 22. However, at this time, it seems likely that both online play and downloadable content will not be likely. Hopefully, they will be able to work these things in anyways.
On the upside, getting a PS3 seems to become a likely path for me now that Blu-Ray is more or less the de-facto standard for hi-definition discs. That, and the new live Genesis release will be available on Blu-Ray as well. 
So maybe I’ll hold out and get Rock Band for that instead. Except that my TV doesn’t handle HDMI, and I don’t know if a DVI adapter will solve the issue…
Minor update: my connection is HDCP enabled, so an adapter WILL work. Woohoo!