Polling the polls: are they gibberish?

Since I’m for McCain, I was pleased to read the Arizona Senator has evened things up with Obama in the new Gallup Poll. But is this real?  Only a few days ago, the LATimes was showing an Obama slaughter.  What changed?  Is it the pump prices and Obama’s non-response to drilling?  McCain seems to have a more coherent and multi-faceted energy plan while Obama seems mired in very old-fashioned anti-nuke liberalism, but still… The question is the polls.  How do we know if and when to believe them?  We are looking for someone to write dispassionately about this on Pajamas Media.  Feel free to leave suggestions here.