Is this what I think it is? Fans vote on sets and Lego makes and sells them in a limited fashion? I see it mentioned all the time on Brickset, but I never see any explanations.

yea its exactly that. every idea needs at least 10,000 supporters. once it does it gets looked at by a Lego jury and they decide if they want to sell it. heres a link to the Lego cusso blog with some articles of ideas getting turned down and being accepted. pretty cool stuff

http://legocuusoo.posterous.com/

Oh, wow. How does one get on 'The List' to buy approved Cuusoos? How much do they cost in comparison to retail sets with similar brick counts?

Apparently Cuusoo means more or less "wish" in japanese.

A Shaun of the Dead set that won enough votes was recently turned down by Lego for fairly obvious content reasons. A BTTF theme and a EVE Online ship have been voted through and are in review by Lego now, and the voting site is getting carpet bombed by votes for a Firefly Serenity playset as we speak. So far the winning sets that have been manufactured have been a Minecraft microscale set (that was backed by Minecraft itself) and I think a real life Japanese unmanned spaceship and some kind of Japanese(?) underwater craft I think.

I guess celebrities have started tweeting about thier pet licenses accounting for the sudden influx of votes for Shaun of the Dead and Firefly in particular.