Yes, there seems to be one on every cabin deck, but not in the same place, just ask your room attendant after you board. There are also irons and ironing boards in those rooms too.
April 13, 2003 Carnival Conquest
November 2, 2003 Norwegian Dream
February 26, 2004 Carnival Miracle
June 4, 20004 American Queen
November 20, 2004RCCL Grandeur/Seas
January 29, 2005 Carnival Sensation
September 11, 2006 Carnival Holiday
We used the laundry room a few times. As I remember, the washer costs $1.50 and the dryer costs $2 (for 30 minutes, but for many items, you will need more time). The soap costs 75 cents for those small boxes good for one wash. I did not bother to bring soap, but you may want to take a small bottle or powder.
On our deck 7 laundry room (near room 7339), there were four or five washers and three dryers plus a sink. The room had one ironing board and one iron. The iron plug was attached to a timer, so this would certainly prevent anyone from leaving the iron on hot for too long.
The ironing room does get busy on the dressy nights (Monday and Thursday) when many passengers want to iron their clothes.
On Thursday, a SMALL laundry bag was placed in each cabin. On Friday morning, if any guest wanted to fill this bag with dirty clothes, the clothes were washed, folded and returned later on Friday for a price of $12. I did not think very many clothes would fit into the bag.
In a balcony room, the small table when covered wth a pillow case and towel could make a good ironing board.