Dead Space: Ignition is out now for PS3 and Xbox 360, not sure about PC.
What it is: animated comic with 3 mini-games. The minigames are very unrelated to the DS universe, and instead of hacking type minigames. I don't know if there's 1 occurance of each of the 3 minigames, or if the story is long enough for each to appear multiple times. Basically you're watching an animated comic and at times the characters get stuck between necromorphs and a closed door, and you have to hack it to get through. From what I've seen the art is not very good, hopefully the setting and story make up for... well, everything else. (I have Ignition but haven't had a chance to start it up yet.) Oh, also somehow you can unlock a suit for Dead Space 2 from within it.
How much it costs: $5 (or free with DS2 preorder) I had DS2 preordered when this came out, and Amazon sent me a code in the mail to redeem my copy for free. I assume one could preorder at Amazon, get the code and redeem the game, then cancel the Amazon preorder.