Swing states are states that are not "safe" for a candidate. Illinois is obviously "safe Obama" and Texas is "safe Romney".
There are 10 swing states, now only eight. The eight left, that will determine the election, are OH, NH, FL, PA, NC, IA, NV, CO. All those states are now leaning Obama in aggregate polling except NC, which should be pretty sure for Romney.
Obama started with more "safe Obama" states than Romney had "safe Romney" states.
Obama was always over 270 electoral votes. Romney was always in the position of having to win votes to get to 270, and still is.
Obama only had to win 1 or 2 swing states to assure victory. Romney always had to win virtually all of them to win.
Florida has had overwhelming (greater than 2008 numbers) early turnout, nearly all Democratic.
TPM.com has a good polling page, where they aggregate the polls, and an excellent reputation for accuracy.
http://talkingpointsmemo.com/ click on "polls" in the header
Nate Silver's FiveThirtyEight.com page also has excellent, accurate analysis of swing states.
www.fivethirtyeight.com