:P :P hey my son is desparate for the tony hawks 3 cheats any news of them??????

Here are some codes that i have found for your son. There are some that he can fiddle around with:

Special always available:
Press Start to pause game play, then hold L1 and press Triangle, Right, Up, Square, Triangle, Right, Up, Square, Triangle. The pause menu will shake to confirm correct code entry. Alternately, complete all the goals in the game and get gold medals in all three competitions five times in career mode with a different skater each time.
Information in this section was contributed by Nick White.

Turbo mode:
Press Start to pause game play, then hold L1 and press Left, Up, Square, Triangle. The pause menu will shake to confirm correct code entry.

Slow motion:
Press Start to pause game play, then hold L1 and press Left(2), Up, Left (2), Up, X. The pause menu will shake to confirm correct code entry.

Extra points:
Press Start to pause game play, then hold L1 and press Square, Circle, Right, Square, Circle, Right, Square, Circle, Right. The level will end with 10,000 points added to your score.

To get first place in competitions without performing a single trick, just press Start at the beginning of each round. Enable the "Extra points" code and you will get at least 93 points without a single trick.
Information in this section was contributed by SweetGuy35297608.

Perfect balance:
Press Start to pause game play, then hold L1 and press Up, Down, Up(2), Triangle, X, Triangle(2). The pause menu will shake to confirm correct code entry.
Information in this section was contributed by ryan ruddy.

Stud mode:
Press Start to pause game play, then hold L1 and press Square, Triangle, Up, Down, Right, Up, Square, Triangle. The pause menu will shake to confirm correct code entry. Stud mode maxes your stats to 10, which may not appear on the player stat screen. Alternately, complete all the goals in the game and get gold medals in all three competitions six times in career mode with a different skater each time.
Information in this section was contributed by Andy Zhou and Baylen Fontenot.

Reversed level:
Press Start to pause game play, then hold L1 and press Down(2), Triangle, Left, Up, Square, Triangle. The pause menu will shake to confirm correct code entry.

Thin skater:
Press Start to pause game play, then hold L1 and press X(4), Square, X(4), Square, X(4), Square to make your skater more thin. The pause menu will shake to confirm correct code entry. Note: Repeat this code to increase its effect.
Information in this section was contributed by Baylen Fontenot.

Weight mode:
Press Start to pause game play, then hold L1 and press X(4), Left, X(4), Left, X(4), Left to make your skater fat. The pause menu will shake to confirm correct code entry. Note: Repeat this code to increase its effect. Alternately, complete all the goals in the game and get gold medals in all three competitions seven times in career mode with a different skater each time.
Information in this section was contributed by Timberwolfsh.

Big heads:
Press Start to pause game play, then hold L1 and press Up, Circle, Down. The pause menu will shake to confirm correct code entry. Alternately, complete all the goals in the game and get gold medals in all three competitions ten times in career mode with a different skater each time.

-I have kept the names of those who have made the cheat available to the public.