Looking at it via Google Translate, it seems to be another project similar to Treasure Castle Labyrinth and Heavenly Gathering of Clouds. In other words, it's essentially the full Touhou package (music, scenario, characters), but without the actual gameplay aspect of it (which is kind of depressing, I'd like to see another actual game by ido :V), although instead of it being a collaborative music collection, ido and Wanwan are going to be the composers and that's about it (others are doing the scenario and characters despite it not being an actual game, more like the framework of one). Which reminds me, I actually did look a bit into Treasure Castle Labyrinth, and not only was the music pretty decent, the bits and pieces I was able to gather from the scripts are pretty interesting too (I kind of wish they were fully translated, but it seems no one wants to).
As for the name of the project, it's called 東方魔宝城 ~ Book of Star Mythology (Touhou Mahoujou ~ Book of Star Mythology, or Eastern Magic Treasure Castle ~ Book of Star Mythology). For some reason, the silhouette on the cover looks like Angra Menog from Devil of Decline, sort of.
EDIT: ...Or I misread the translation, the part I thought that said "this isn't a game" just means something like "we're only doing the music, we have nothing to do with the danmaku." So this IS going to be a game as far as I can tell. Ho boy, this is something to look forward to, even if it's just because I enjoy Wanwan's music. :V
Second Edit: Also, this game's apparently getting released at the next Autumn Reitaisai, so that should be roughly November-ish (I don't know when this year's is, I looked it up and I saw November was when last year's was, so about then).