Unlock Unlimited Creation Points

Got to Rosters, then Edit Player.  Select the players you wish to be rated "99".  Next, go to his attributes and simply raise every bar.

Unlock the Mummies Team

Use a memory card that has a saved file from a EA Sports racing game.

Unlock Barry Sanders

Get a gold ranking in the RB Ground Attack drill in Mini-Camp Mode on the All-Madden Level.

Unlock Deon Sanders

Get a gold ranking in the DB Swat drill in Mini-Camp Mode on the All-Madden Level.

Skip a Music Track

While at the Help Menu, hold Square and press R1 or L1.