I did a little Black Library story recently, for a Deathwatch project that turned out to be the tie-in story collection for the Deathwatch: Overkill boxed game. My story is ‘The Known Unknown’ and involves Jensus Natorian, a Blood Raven Librarian with serious mentor issues. I think it turned out really well.
You can buy either the story as a standalone ebook or the whole collection, Deathwatch: Ignition in either ebook form or hardback. I haven’t read any of the other stories (or seen the game – one of the interesting things about a job like this or the Fellguard stories is working from a brief that’s perhaps a page or two of notes), but there’s some good people in there like Braden Campbell (whose Dark Eldar story in Fear the Alien was great) and Doctor Who books alum Steve Lyons.
Not sure what the book’s distribution will be outside hobby shops but you can get it either from your local Games Workshop or via the website:
One more Black Library thing due from me, if the stars align. Later about that.