Somewhere I saw this listed. Maybe on the celebrity site or on Cruising Power, the travel agent Celebrity site. I don't remember. It was enough that I told my husband he had to bring enough underwear, but low enough that I said he could get shirts done, and I'm probably going to have my dresses pressed. I did that last time and it made me feel wonderful to have a beautifully pressed dress to wear.
The info is on the Celebrity site, but it isn't easy to find. It is under FAQs (on the lower right), and then stateroom and ship services, irons & ironing boards - and maybe another place. It lists all the prices for laundering, dry cleaning, and pressing.