Are you talking about the replacement model for the foglights? If so, you will find them in this comprehensive list below. I think that is what you are looking for. Hope this helps...
2006 PONTIAC GTO
Low beam headlamp
H11-55W
High beam headlamp
H9-65W
Parking light
1157A
1157AST Silverstar Signal Lighting: Complete the Look: Crisp, Clean, Style
1157ALL Long Life Upgrade: Up to twice the life of the standard lamp
Front turn signal
1157A
1157AST Silverstar Signal Lighting: Complete the Look: Crisp, Clean, Style
1157ALL Long Life Upgrade: Up to twice the life of the standard lamp
Rear turn signal
1156A
1156AST Silverstar Signal Lighting: Complete the Look: Crisp, Clean, Style
1156ALL Long Life Upgrade: Up to twice the life of the standard lamp
Tail light
1157
1157LL Long Life Upgrade: Up to twice the life of the standard lamp
Stop light
1157
1157LL Long Life Upgrade: Up to twice the life of the standard lamp
Fog/Driving light
9040
Back up light
1156
1156LL Long Life Upgrade: Up to twice the life of the standard lamp
Front sidemarker
168
Glove box
6418
Map light
DE3175
Step/Courtesy light
161
6418