In fact the Xbox Live marketplace has it right now, and they say it weighs 1.85GB. PS3 gamers need to wait until July 4th for their longer credit roll. The PC copy isn't out just yet.
The studio acknowledges that this still won't make everybody happy, and reaffirm that this "does not fundamentally change the endings," but expands on their general meaning for the future.
The general complaint, outside of the choices we get left with, are that each of the endings were too generic and show nothing in the way of 'our Shephard's journey', meaning that decisions we've made throughout the series didn't get so much as a passing glance. The Extended Cut DLC will change that.
"It provides more of the answers and closure that players have been asking for," reads the .
"It gives a sense of what the future holds as a result of the decisions made throughout the series. And it shows greater detail in the successes or failures based on how players achieved their endings."
"It does not," the FAQ continued, "fundamentally change the endings, but rather it expands on the meaning of the original endings, and reveals greater detail on the impact of player decisions."
In order to experience the Extended Cut content you'll need to either replay the game or load a save from before you launch an attack on the Cerberus base. Sorry for the mild spoiler there but given this deals with the game's ending it's more than likely you know exactly what's going on. The Xbox 360 DLC is out now; PC should be soon.