Technically, irons are not allowed in the staterooms. Depending on what cruiseline you choose, there may be ironing rooms. Disney is the only ship that I have seen with these rooms, however.
Although irons are not allowed in the stateroom, I take one anyway. I figure that the iron isn't anymore dangerous then my straightening iron for my hair. Sometimes I use the iron and some trips, I don't touch the iron. If I do use it, I quickly iron on the bed and then take the iron over to the desk to cool off (then I hide it away from anything flameable).
I also use the fabric wrinkle remover in a can. It works wonders and is made by Magic.
Another suggestion is to place each of your hanging clothes in a separate plastic dry cleaning bag. For some reason this works to keep the clothes from wrinkling in the hanging clothes bags.
I also use a "rolling" method for my shorts and shirts (shirts placed inside of the shorts/pants) before placing them in the suitcase.
Hope this helps! :