Legend of Grimrock is available for pre-oreder right now through GOG.com and grimrock.net at 20% off. It'll also be out on Steam but as of writing this it's yet to show up there.
The game looks absolutely awesome and everyone should get it. If you have any sliver of nostalgia for games like Eye of the Beholder, Dungeon Master or even Stonekeep, you'll probably soil yourself when you play it. I know I'll be keeping a fresh pair of underwear handy.