Note: Make a backup copy before you edit the ini file.

Edit the "splintercell2user.ini" file in the "\splinter cell pandora 
tomorrow\offline\system" folder using a text editor. Bind one of the following 
codes to a function key and press it during game play to toggle the corresponding 
cheat function: 

floating: fly 
freeze enemies: playersonly 
gives health: health 
god mode: invincible 1 
god mode off: invincible 0 
more ammo: ammo 
kills all enemies: killpawns 
no clip mode: ghost 
no clip off: walk 
Sam is invisible: but enemies can still bump into him and start alerts. invisible 1 
spawn airfoil round: summon echeloningredient.eringairfoilround 
spawn disposable pick: summon echeloningredient.edisposablepick 
spawn flashbang: summon echeloningredient.eflashbang 
spawn frag grenade: summon echeloningredient.efraggrenade 
spawn smoke grenade: summon echeloningredient.esmokegrenade 
spawn sticky camera: summon echeloningredient.estickycamera 
spawn sticky shocke: summon echeloningredient.estickyshocker 
spawn wallmine: summon echeloningredient.ewallmine 
turns off invisible: invisible 0 
unfreeze enemies: playersonly 0

Just press any keys during gameplay.