Temparture should not get lower than 70*F and should not be higher than 100*F. For Green Iguanas to digest food, the tempature should be above 80*F.
Water
Iguanas should have fresh water everyday
Food
25% to 40% should be greens
25% to 40% should be vegatables
10% of fruit
5% to 10% commerical food (Iguana food)
Sunlight
Babies and adults should be taken out to get sunlight to help prevent Medicbalic Bone Disease, or MBD. (Make sure your pet has gone to the bathroom before hand, so you don't get "little surprises" on it.
Heat and Light
You should have at least two sources of heat. The first is a basking light, baby iguanas especially like to stay under it alot. The second source is a undertank heater, this way the little guy stays warm all the time. You also need to provide a UV light which helps prevent MBD.