Bonus teams:
Press Circle at the team select screen for a Super Bowl team. Press Circle, Circle at the team select screen for an All-Star team.

Best created player:
Go to create super player, then for the attributes press Right, Right to get the best player in the game.

Super Bowl/Great Teams:
In the preseason mode, at the team select screen, press Circle once to get the the NFL greats on the team of your choice. Press Circle again, to get the Super Bowl teams.

Various Cheats:
Go to the cheat menu to enter these codes

Players Faster BOOSTER
Players are 2D TWO D
Strobe STROBE LIGHT
Receivers catch better STICKEM
Long Passes SHOOTERS
Tackles are Harder CRUNCH
Giant Players GIANTS
Defense better LINE BUSTER
Super running back SUPER FOOT
Big ball BIG PIG
More hits JACKHAMMER
Injuries frequent HAM INJURY
Opponent kicks are bad AIR CPU
Get GameDay Field GD FIELD
Faster fatigue FATIGUE
Last season players OLD SCHOOL
All players the same stats ALL EVEN
Players don't fatigue ENDURANCE
Basketball players BASKETBALL
European league stars EURO LEAGUE
Programmer players RED ZONE
U.S. President players OVAL OFFICE
Tiny players FLEA CIRCUS or TINY GUYS
Small, fast players POP WARNER
Super special moves SPECIAL MOVE
Tall and skinny players STICK MEN
Turbo mode COFFEE BREAK
Unbeatable team UNBEATABLE
View game credits CREDITS
989 Studios players 989 SPORTS
Get Bobo teams ALL BOBO
Ball carrier has speed bursts ROCKETMAN or ROCKET_MAN
Get cheerlears after game FASHION SHOW
Easy Mode CHEATERS
Hardest mode SMARTER CPU

Extra Teams:
Go to the team select screen and press Circle 1 time for great teams or Circle, Circle for super bowl teams.