Bonus teams:
     Enter  exhibition  mode,  then repeatedly press L2 + R2 until the
sound  of  a  dong  is  heard.  The  Dingers and Islanders will now be
selectable under the 90's teams.

Get the superteam dingers:
     To  get the superteam dingers in batting practice go into batting
practice. Next go to the player select. All at once press R1 + R2 + L1
+  L2.  If  you  do this right the screen should switch to the dingers
team.