Super Men's Team
At the Team Selection screen, move the pointer to the top left corner. Then press Down, Right, Left, Down, Down, Right, Up. Now change the team name from WHEN ISNT IT? to WHEN IT IS. (including the period).

Super Women's Team
Select Make Team and perss Down, Right, Left, Down, Down, Right, Up, Up, Down, Up, Down, Up. Change the team name to WHAT IS A WREN? (including the ?). Then change the name to A BIRD. (including the period). Then change the name to WHEN ISNT IT? (including the ?). Finally, change the name to WHEN IT IS. (including the period).