PolitiFact.com says "by the end of 2011" [1]. Looks like this announcement puts him on track to meet this campaign promise on the nose.
PolitiFact also has a more comprehensive set of Obama's campaign promises kept and broken [2]. Interestingly enough, most of the broken promises seem to be directly related to the GOP's efforts to keep the Bush tax cuts and prevent Obama from increasing spending for education, health care, environmentalism, and humanitarianism. [3]
I think going back on the promise he made in 2008 is more an indication about the entrenched power in the U.S. and the difficulty of making such a proclamation without knowing exactly what it would entail. For him to go back on this now would be a major blow to credibility. I doubt very much that he would announce this only to backtrack in a couple of months.
