Microsoft's Major Nelson confirmed today that Assassin's Creed 2 will be the next free title release in the Xbox "Games With Gold" program. It will be available on July 16, as the first title released this month is Defense Grid: The Awakening.
Initially, there was some confusion regarding which games would be available this month. It was originally thought that Assassin's Creed 2 and Halo 3 would kick off the program as the first free games, but as it turns out those were only mentioned "as part of the program" and that "no date was given for their release."
Whatever the reason, whether it be fan reaction to that news, Microsoft has decided that AC2 would be a smart choice for the second game this month. As a reminder, you'll be able to download the game for free on Xbox LIVE as long as you are a Gold member.