Hey I have a question.

I saw that on Wed 7/27 Mexico played Brazil. What was that game for? I didn't hear anything in the news about a big match coming up and Brazil/Mexico would usually get some press build up?

Luck works itself out over time (bad and good).  I agree, the Canadian "goal" shouldn't have been called back, but over the course of the tournament I'm sure the U.S. had plenty of calls go against them as well.

There's no appeal process to overturn calls during a game.  The only way a call can be overturned is if the linesman speaks with the referee and decides an incorrect call was made, but the coach can't appeal (they can scream though!).  As for instant replay, I don't know if it's being considered in world soccer, but it is a current topic of dicsussion in the English Premier League.  The traditionalists think the idea is terrible, but it could really help the game.  After all, why not use the advances in technology to better the sport?