Sandie-
I bought plain white pillowcases from Wal-Mart. I then washed them to take out some of the sizing and then bought iron-on transfers and used my home computer printer to put clip art of Disney characters on them, with each child's name, the name of the ship and the dates.
Even if GS gets snooty with me and tries to not let me get them signed, they are still cute souveneirs this way.
Hope this helps!