Well, something caused a jump for O in the poll.
It really needs to be tightening a bit every day, not seesawing back and forth.
These variations are within the margin of error. Since the total sample size is probably less than 1000 people, just randomly grabbing people will give a potential variation of several percent any given day. Some days you get a few more McCain voters than you should, other days you get a few less.
Nothing to fret about. It doesn't mean obama is gaining. But if the lead stays about even, that isn't great. Then we need to see if these folks are oversampling dems, too.