Next Level Games has revealed many details about how the Mario Strikers Charged online set-up works.
For the lazy:
-Matches against random people in your area as well as the expected Friend Code matches.
-A 'season' mode where you earn points from online matches and win achievements.
-Online tournaments being possible (not planned yet, though).
-4-Player online matches where you can play with a second person locally.
I know; different developer, different type of game...but they're still good ideas that could be implemented in Brawl. We're just going to have to wait and see.