Each day there will be someone at the door of Mambo's restaurant to take reservations for ALL of the restaurantson the Pearl. They will also have menus for each of them. We boarded immediately after boarding began and someone was there when we passed it shortly thereafter.
When I was aboard the Dawn in Dec. 06 I went directly to each restaurant shortly after boarding and made reservations for every other night of the cruise for a specialty restaurant -it worked quite well. You can obtain a cruise menu for your cruise at the Purser's desk upon boarding and you can plan your dining options for your palate and personal plans using that as a reference-free style works well!