Gallup's daily tracking poll is now composed of only post-Sunday interviews, and so Gallup is proclaiming the official Dead bin Laden rally as six points: Barack Obama's approval score went from 46% on Sunday to 52% today.
Two things: first, my guess is that it would go to 60%. If it's really 52% (and it may still go higher over the next few days, although of course it may rapidly recede), then my guess was pretty weak.
Second, though, on that "six" points...remember, Gallup's daily tracking poll is new. It's not unusual for Gallup to run a poll soon after a potential rally effect (although that's not always the case, going farther back in time), but until recently the "before" number could have been taken anywhere from a day to a month before the rally event. If that had happened this time, the rally could have been recorded as anything between the six point recorded (based on an April peak 46% achieved on April 1, 2, 3, 4, 11, 30, or May 1) up to a high of 11 points (based on an April low of 41% reached on polling ending April 14 and 15).
There's not all that much at stake here. If you really want to measure this particular rally, my advice is to use a good poll-of-polls, such as the one at Pollster, and to wait another week or so before seeing how it all shakes out. If you want to know about rallies over time, you can gather enough of them that those types of error wash out. But comparing this particular rally to specific historical rallies is going to be difficult, because we just don't have precise measurements before the days of multiple, frequent polls.