Slowshot is right, though, American football is insanely complicated. There are tons of rules, tons of penalties, tons of strategies, that all collide at once in 2 to 12 second plays.
People that don't understand it will complain about the downtime between plays, but those people do not understand the intricacy and planning involved in these plays. Think of each play like an extremely fast and full contact chess match.
It will likely be difficult to learn from the ground up unless you are really interested.
BTW, right now, the playoffs are going on, so there's only a few games left in the season. After it's over, it won't start up again until September.
As far as teams, well.. he's right about the Dallas Cowboys. The New Orleans Saints is another team that a lot of people are getting into right now because they've historically been one of the worst teams in NFL history, but they've recently gotten very good and all the hurricane Katrina drama makes it interesting.
There is also a lot of interest in the Tennessee Titans right now because, although their record isn't that great, their rookie quarterback has recently been doing extremely well and they seem to be on the rise. Their quarterback, Vince Young, was an astonishing and very unorthodox QB in college and he almost single handedly won the college football championship game last year. He struggled early this year when he moved to the NFL, but he has improved a lot.
You can check http://www.nfl.com/standings to see team's records. To give you some ideas, some teams that have the potential to do well, but are not without major flaws, Carolina Panthers, Cincinnati Bengals, Jacksonville Jaguars, Philadelphia Eagles, Denver Broncos, NY Giants, NY Jets, St. Louis Rams and Pittsburgh Steelers.