How accurate are polls?

I mean, think about it...when was the last time YOU participated in a random phone poll. I think I have once, back in the 80's. And how do they work? Is it a live person asking you a questions, or a computer? In this day and age, with people leery of phone scammers, does anyone answer questions posed by a stranger on the phone? And, what type of people DO answer those questions? Are they mentally challenged or just gullible?

I think what I'm getting at, is that I'm only sort of worried about polls that show McCain in a tight race with Obama. To be honest, I doubt if polling reflects how the race is going to turn out...I'm posting a map here with the latest projections from a website called fivethirtyeight.com. They have Obama winning, but just barely. And I'm finding it difficult to believe that McCain is going to kick Obama's ass in states like Georgia and Mississippi and Louisiana that have African-American populations in the 25% range. Voter registration is up among the African American population all over the country and I'm pretty sure that thousands, if not millions of black Americans, particularly young, black Americans, who have never bothered to vote before, are going to come out in droves. Obviously that won't be enough to win every state, but it seems to reason that in some states, the black vote is going to make a huge difference and could possibly turn the vote count in Obama's direction or at least make many states very close to call and I'm kind of frustrated at not seeing that being discussed much in the press.