just take the very tip off. and be carefull when handling. thats all i do with my big guy and the scratches arent to bad. i get a few every now and then..
as far as care goes. do a search on this forum. there has been alot of iguana talk lately. lots of good advice. and some good pics to. check that out and read that it will help you out.
i also recomend the book Iguanas for Dummies. lots of great info in there as well. it makes a real good reference book to. incase you need alot of info quickly.