For those of you totally confused by pollsters and their methods--given the different conclusions they seem to come to--you should look at this very clear explanation of their differences and similarities by E.J. Drummond. Also see The Horserace Blog for thoughtful commentary on polls and polling. After examining the various national polls and their methods, Horserace Blog says this:
"So...what does this mean? Essentially, it means that the reliable polls are, roughly speaking, Time, Battleground, Gallup. All of the rest skew toward Democrats, and should be viewed with caution. A surprising number of the rest are either using questionable methods or are using unadvertised methods. This is absolutely taboo among social scientists. Methodology is the only element that the researcher can control, and thus it is critically important -- indeed it is an ethical responsibility -- for the researcher to make his/her methods avaiable."
Time, Battleground, and Gallup. Keep your eyes on those.