Good poll overview/comparison here: http://realclearpolitics.com/polls.html

By the way, I think I heard somewhere that no one has come back from an 11 point deficit (at least in September) to win the presidency. Kerry had better take Clinton's advice (i.e., shut the hell up about Vietnam) if he still wants to win. I would also advise him to avoid the topic of the war on terror in favor of bashing Bush on the economy, which is his only hope, in my opinion. Unfortunately for Kerry, that water is very muddy; there are some good economic indicators and some bad ones, so the case for Bush blowing the economy is certainly not an easy one to make.