Leaving Practice Area:
When you go in the Practice mode, and play. Go to the fence in the on end of the ramp, here you must lay down, allot and then just only slip through, now you're out of the practice area and can skate on the road, enjoy...

PS. I've tested this, it works! but its very hard to do! Tested on PC and PS2!

All Levels:
Type:
Watch_me_xplode in cheat menu

Get Moon Gravity:
Type:
MOON$HOT in cheat menu

Matrix Mode:
Type:
FBIAGENT in cheat menu

Special Always On:
Type:
I'MYELLOW in cheat menu

Perfect Rails:
Type:
BELIKEERIC in cheat menu

Perfect Manuals:
Type:
FREEWHEELIE in cheat menu