Steal! is a yaoi game by Spray, the same company behind Gakuen Heaven and Kichiku Megane. It's also the source of the pic in HFG's previous post. A piece of artwork from the game was first posted on HFG in a Misfits post.
I don't know exactly what the game is about, but judging from the pics I've seen, it looks to feature students who are assassins by night. It's like a dark twist on Gakuen Heaven.
If anyone knows who did the character designs/artwork for the game, let me know. Below, you'll find more pics from the game.
Image Archive (.zip)