The facts: Gallup's results are a three day rolling average of daily poll of 1,500 adults. Telephone poll, no mention given of mobile phone handling. MoE 3.
And the result for August 25-27 came up with the shocking result: Obama's approval is at 38, while disapproval is up to 55, slightly worse than the 20-22 result of 38/54. For context, George W. Bush at the beginning of September 2008, September 8-11 was at 33 approval and 65 disapproval. Obama's approval is only 5 points away from matching Bush at the very end of his Presidency, the month of Obama's own electoral win.
So while it's not yet appropriate to say that Obama has grown to be as unpopular as Bush, the trend just might take him there by election day 2012. Then again, it might reverse. But I don't know offhand whether any President has managed to come back from figures this bad, to getting back in the black with approval above disapproval.