During the Xbox One's press conference, Microsoft announced that Xbox Live users will receive 2 free games each month. Xbox Live users can download Halo 3 and Assassin's Creed 2 for free in July and Fable 3 for the remainder of June.
Microsoft's Games With Gold will somewhat replicate the free offerings of PS Plus but will limit the amount of games available to 2 games per month. You can download the first game of each month on the 1st and then the second game on the 16th. Xbox live users can only download the promoted game during the half of the month they remain available. The game will then be removed when the new game rolls in.
Unlike the PS Plus service however, the Games With Gold promotion will provide access to the free games forever, not just when the user pays for the subscription. If you download the game, you own it. You do not need to renew your subscription to gain access to the games once your Xbox Live expires.
The Games With Gold promotion will last until the end of the year so stay on top on the free games to make sure you don't miss out.
Source: Xbox.com
