Tamming your new pet is not hard it just takes patience. It is in a new enviroment and has no idea you are it's only friend. I tell people to treat as a stray cat,one that you want to earn it's trust so it will come to you.
Take a towel and place in your hand take the Iguana slowly out of the cage, CAREFULLY. Make sure toes and legs are not bent so you will not cause a break. Pet the iguana on the head softly. Feed it a treat out of your hand.(He may not eat from your hand at first be patient) Do this for about five minutes at a time at least twice a day. This should only go on for about a week or so. Then you should still use the towel but let him crawl on you for a few minutes he will probally go for your shoulder or head. Then place him back in the cage. This should be done for another week. Then try without the towel and remember always have a treat to feed him. He will associate you as a treat also. A treat should be something he only gets when you are holding him or her.
The iguana is not a mean a creature by nature it is a deffense one. It is only trying to pertect it's life. A new owner and enviroment takes some getting used to. Imagine someone taking you without your permission and placing you in a strange enviroment and cage. You would probbally be alot meaner than the Iguana.
GOOD LUCK and remember the Iguana is captive if it is in your home and is totally reliable on you. Even if it is not the most well behaved one.