So, when the polls come out as "even", it almost certainly means that, as of today, McCain would win by 4%-5%. Of course, the poll numbers will go up and down over the next two weeks with the conventions, and so on. Kerry was leading by nearly 10% at this point 4 years ago, for example. Democrats tend to slide, as we get closer to the election. That's been true in every Presidential race going back to Jimmy Carter.
What's really ominus for McCain is that the polls don't reflect all the newly registered democrats as they use cell phones and the new VoIP telephone lines.
Cell Phones and VoIP lines don't get those annoying pollsters as much as land lines and simply can't be counted in the polling.
another problem is the pollsters that advertise to give the results you ask for. When zogby and rasmussen get paid to deliver the results you pay for, they can simply call their republican buddies up and say what do you think? Then of course your going to get a majority of results favoring the republicans and they are so skewed, they make the averages look close.
When you base a poll on collecting 1000-2000 respondents, they are not even worth quoting except if you are a media outlet looking to sell advertising. Then you'll want to apease your viewers so they buy products from the advertisers and you'll want to apease the advertisers too.
Advertisers know the democratic base is made up of middle and lower class people that will have trouble affording those products anyway because of what the republicans have done.