I mentioned this in early July, but it bears repeating:
I have written a new Laundry Files novella, titled "Equoid" (if you're interested in continuity, it's set between the events of "The Jennifer Morgue" and "The Fuller Memorandum", after "Down on the Farm"):
Tor.com (cover on left) will be publishing it on their web site on September 30th, and selling it for $1.99 as an ebook on October 16th. If you enjoy it and want your very own copy, consider this a way of giving me (and my editors) a kickback. American ebook store links can be found via the menu here; so far the only UK store I have a link for is Amazon.co.uk.
If you want the deluxe limited edition signed hardcover, Subterranean Press (cover on right) are going to publish it in 12 months' time. They're planning on printing just 500 copies of the signature run, illustrated by Steve Montiglio (who did the covers for the original Golden Gryphon editions of "The Atrocity Archives" and "The Jennifer Morgue").
As for your questions: (1) it's a novella, meaning it's about a third the length of a full novel (around 100 pages), (2) I'm not going to tell you what it's about, (3) there should be no DRM on the ebook (if there is, let me know and Tor will get it removed), (4) if this leaves you wanting more Laundry Files, you will have to wait until July next year, when "The Rhesus Chart" is due to be published (it's officially In Production—meaning, on its way to the copy editor—as of last Friday). Anything else? That's what the comment thread is for!