Someone from the Battlefield 3 forums unearthed a poster that purports to reveal plans for the extra maps included in the game's limited edition. A four-map redo of the "Strike at Karkand" map from Battlefield 2 will be included.
Furthermore, for those who don't pick it up free in the Limited Edition, it'll be available for purchase a month after the game's autumn 2011 release.
Strike at Karkand is an urban combat map from Battlefield 2. According to the Battlefield wiki, it's the most popular online map, and Battlefield 3 forums have certainly been asking for its inclusion in the new game.
It looks like someone picked this off of a European online store by running a URL. Currently, Electronic Arts is saying that details on the DLC will be available in February. Given Karkand's popularity there's a chance this is wishful thinking from someone in the community with an image editor.
I've pinged an Electronic Arts representative; if we get any reply, it'll go here.