Three cheats

If you connect the Gamecube with the Gameboy Advance at the Game Settings screen, you will unlock three cheats.
These are:
Code                    Effect
Big Ball                Makes the ball huge
Walls                   The ball does not exit the field
Flying                  The players bounce around like bunnies


Unlockables
Unlock team's third kits.

Just beat the teams in this 6 leagues.
Unlockable              How to Unlock
English Premiership Teams	Beat all the teams in this league
French Ligue Teams      Beat all the teams in this league
German Bundesliga Teams Beat all the teams in this league
Italia Division 1 Teams Beat all the teams in this league
Rest of the World Teams Beat all the teams in this league
Spanish Primera Teams   Beat all the teams in this league