More cheats available at: http://www.cheatprovider.com

Aggressive Inline
Low-Gravity Wallrides:
Enter U, D, U, D, L, R, L, R, A, B, A, B, START on the Cheat Menu.

Unlock every Character:
Enter D, R, D, L, D, L, D, R, R, R on the Cheat Menu.

Unlock Power Skates:
You just need to re-enter a completed level to pick up the power skates.

Unlock Ultra Skates:
Complete all the levels with 100%.

Enter the following codes at the Cheat Screen:

Skeleton:
All Keys

Bakabaka:
Juice bar always full

Bigupyaself:
Juice bar always full

Justinbailey:
Perfect Handplants

Quiezdontsleep:
Perfect Manuals

Jonesin' for some secret characters? If you can finish all of the normal and hidden challenges on each level, you will unlock someone else to get aggressive with. Here's the list:

Movie Lot:
The Bride

Industrial:
Junkie

Cannery:
Diver

Museum:
Mummy

Civic Center:
Goddess