Hi there, all food served in the cafeteria(s), and main restaurant(s) and sent to your cabin with room service (with some exceptions here) is free, gratis and for nothing. There is a charge made if you visit speciality restaurants and some of the speciality coffee bars. There is also a charge on some ships for ice cream, as with Princess, but in the main food is free and available almost 24/7.... Neil.
Agree with Neils answer if you get the 2009 Royal Caribbean brochure it will give you the best break down of what you get and what you pay for including the air fare if thats applicable? and on the back cover what you need to know about tipping.