God, fly, weapons, ammo, speed, level select command line cheats:

Download and install the 3 patch (the patch are only on the UK site) 

ftp://ftp.eidos.co.uk/pub/uk/tomb_raider_AOD/patch 

Run the game with the following command line paramaters:

traod_p4.exe -godmode -debugkeys -selectlevel 

-godmode : all weapons, unlimited ammo, all body upgrades 
-debugkeys : fly-cheat, god mode (when flying), more speed ? 
-selectlevel : level select dialog 

NOTE: 
if you use -debugkeys, press F3 to get rid of all the numbers on the screen 

Flying Lara, restore full helath, god mode, come back to life:
Press the B key. Lara Croft will now swim freely through space, pass through walls 
and be in god mode. press CTRL to stop. you can use this cheat to restore full 
health, even after you die. 

Secret training area:
At the beginning of level one (Parisian Back Streets) you'll find a door to the right 
which is locked during normal play. press B to engage the fly-cheat and go 
through the door. you'll discover a secret training area which is mostly complete. 

Fighting:
When your character is near an enemy, tap the action key once for a single punch 
and twice for a double punch. press the action key firmly to kick. 

Silent neck-breaker move:
while in stealth mode, press the action key when your character is standing 
directly behind an unsuspecting enemy. 

Stealth:
While in stealth mode with a weapon drawn, use the right shift key and mouse to 
move the field of vision. as you move your character, your weapon will also move, 
enabling you to target manually. 

Last chance grab:
If your character begins to slide on the scenery, press the action key to make the 
character grab before falling to their doom. 

Rope:
Press the duck key to tuck your character's legs up to rest or avoid objects.


Gain access to Bouchard's hideout early:
After you talk to Janice (the prostitute), run towards the canopy with the stack of 
money under it. From there, turn around and walk to the manhole cover until the 
hand appears. Press [Action] and Lara will climb down into the sewer.

Fire more rapidly with shotgun or handguns:
Instead of holding [Action] to fire, quickly tap it repeatedly. Lara will shoot the 
weapon much faster, making it easier to eliminate targets. 

Get gas masks early:
Stand directly in front of the cabinet and press [Crouch]. When the hand appears, 
press [Action]. If done correctly, Lara should reach through the door while 
crouched and grab a gas mask. This may also work in other places.

Defeating mummy-type knights:
Engage the knights in close combat. Kick or punch them off a nearby ledge to get 
rid them for good.

Parisian Ghetto: Unlimited money: 
Go into the pawn shop after you talk to the women. After you talk to the man in 
the pawn shop, leave. Then, go straight until you get to a sewer drain cover and 
an object or item toward your left. Pick it up. It will be money. Go back to the 
pawn shop. Then, walk back out of the pawn shop. Return to the sewer top where 
you found the money. There will be money there once again. Continue doing this 
for unlimited money.