The chart says it best:
Obama is slightly outperforming Bush (58 percent to 61 percent) and performing significantly better than Clinton (61 percent to 53 percent).
Gallup writes that, after early spikes, Obama's job approval appears to have leveled off and is consistently around 60 percent. Obama support comes largely from Democrats.
The Gallup tracking poll is conducting by combining three days worth of data from rolling surveys taken daily. There is a margin of error of plus or minus 2 percentage points.