Many people have been wondering why this hasn't happened yet, since the manga is fairly popular. I recall there were rumors of the manga-ka declining offers of an anime adaptation, but it seems that is no longer the case:
It's about time. I've been collecting the manga from Del Rey as a lighter balance to Tsubasa and xxxHolic. This is no Naruto but it's a fun read, and its sense of humor really helps prop it up. The anime should erabrace its craziness with gusto.
With any luck, this will cleanse the memory of the Rave Master series.
Meh, they took a liberty in that spread. In the manga, Grey just strips to his boxers out of habit. Hopefully the anime is faithful to this, rather than indulging in extra fanservice for its own sake. It probably will be.