Cortosis:god mode/invincable Grandmoff:all costom costumes.Katan:maxes all froce powers.Vergence:infitne force power.Lightsaber:gives your lightsaber the powers of HULK!!!!. TIP:Wereing costumes such as chopp'a,mara jade,51st legion,darth vader and the empror will stop playing the cut sences. HAVE FUN CHEATING. COBAR.

It's pretty simple. I just put it in to see if anything happened. Put in SITHLORD and you will get the Darth Vader costume.
Other cheats are:
CORTOSIS: Immune to all damage
SPEEDER: 1,000,000 Force Points.
VERGENCE:Infinite Force Power.
GRANDMOFF: Unlock all bonus costumes and Sith Stalker costume. That costume is my personal favorite.
LIGHTSABER: Massive Lightsaber damage
*Note:Using the bonus costumes like Mara Jade, 501st Legion, etc.(except Sith Stalker) the cutscenes will be deleted.

Enter the following codes at the extras screen

Grandmoff:unlocks all costumes
Cortosis: god mode/ invincable
Katarn: maxes out all force powers
Vergence: unlimited force powers
Tyranus: unlocks all force powers
Lightsaber: gives your lightsaber powers of the hulk!!!!!!
Speeder: gives you 1,000,000 points for force upgrades butu wont need it if you use max all force powers>
Ok now that you are invincable and on you're way to become the most powerful I just want to spoil the game the apprentace dies at the end!!!!
Ok by the way I have beaten the game 3 times in under 12 hours non stop

Enter grandmoff on the cheat code screen

You now have all outfits and can play as any character in story mode