Sweden isn't scoring many goals -- only 2 in their first 2 games and has a solid defense. The states is much more able to put the ball in the net but haven't been up against a good defense yet. The US has already won the grouping as long as they don't lose today (a tie will do it for them with goals for and against. Both teams will be happy with a 0-0 or 1-1 result.
I wouldn't be too confident betting on womens soccer. These chicks don't have any control over themselves. They might get 4 PK's if the ref actually calls the game correctly, or maybe one team will get some red cards. It's a coin toss with these girls.