All levels
Pause the game, then press Circle, Up, Down, Square, Triangle.
All tricks
Pause the game, then press Down, Left, Up, Right, Down, Left, Up, Right.
Huntington level
To unlock level 8 (Huntington), go to the big gray ramp with a blue streak on the bottom that is in front of a wall. Go off the ramp, and do an air trick (e.g. Christ Air). If you hit the wall in the middle of the trick, you will land it perfectly and get full points.
Have All Stats Tricks & Inifinit Grind
Pause the game in tournament mode then press up, down, right, circle, triangle, triangle, square, l1, r1.
All Skateboards
At the start menu press and hold L1, R1, then press circle, triangle, triangle, left, left, up, square. you will hear DONG when entered.
Unlocking players
Place second or first in Huntington in tournament mode. You will get a photo shoot complete it by (there is a place that you can go from a rail to a rail to a picnic table to a picnic table) you grind on them and earn 8000 or more points by grinding and depending on the person you are using you will unlock secret players.