To activate these cheat codes, you need to start a new game, then enter "Decter's Dinner" and go to "Enter Code":

EN11K5 - Battle Droid (Commander)
987UYR - Battle Droid
KF999A - Battle Droid (Security)
LK42U6 - Battle Droid (Geonosis)
LA811Y - Bobba Fett
RS6E25 - Clone (Episode III Walker)
N3T6P8 - Clone (Episode III Swamp)
BHU72T - Clone (Episode III Pilot)
ER33JN - Clone (Episode III)
F8B4L6 - Clone
14PGMN - Count Dooku
A32CAM - Darth Sidious
H35TUX - Darth Maul
VR832U - Disguised Clone
DH382U - Droideka
19D7NB - Geonosian
SF321Y - General Grievous
U63B2A - Gonk Droid
ZTY392 - Grievous' Bodyguard
PL47NH - Jango Fett
CBR954 - Kit Fisto
DP55MV - Ki-Adi Hundi
A725X4 - Luminara
MS952L - Mace Windu (Episode III)
R840JU - PK Droid
92UJ7D - Padme
BEQ82H - Princess Leia
L54YUK - Rebel Trooper
PP43JX - Royal Guard
EUW862 - Shaak Ti
XZNR21 - Super Battle Droid

The codes below needs activation in the "Extra" menu when you press "ESC" after you have entered them like the above cheat codes.

IG72X4 - Big Blasters
SHRUB1 - Brushes
L449HD - Classic Blasters
4PR28U - Invincible
LD116B - Minikit Detector
RP924W - Moustaches
YD77GC - Purple
MS999Q - Silhouettes
NR37W1 - Silly Blasters
PUCEAT - Tea Cups