On the back of Sega announcing a third Aliens project in Rebellion's Aliens vs. Predator (planned for early 2010) it seems they are cancelling the Aliens RPG that was in development at Obsidian Entertainment. As a direct result the developer laid off 20 people. The rumour first appeared at Kotaku and has been verified by Joystiq, who also add that all of Obsidian are in trouble.
Rumours also have it that Gearbox Software's Aliens: Colonial Marines may have suffered the same fate or perhaps development has just been put on hold. No official word from Sega yet.
Sega's recently presented a very poor result for the first nine months of their fiscal year and these decisions appear to be an attempt to cut expenses.