Yes, all the food is included ... except if you decide to go to Sabatini's which costs an extra $15 per person ... or the Sterling steak house or the Cajun restaurant and I think both of those cost $10 per person - depends on what ship you're sailing on whether or not these options are available.
Other than that there's 24/7 dining ... from the dining rooms and pizza parlor (limited hours) , to the Horizon Court to room service (where you really should tip a $1 or $2 per person depending on what you order) and they are all included in the price of your cruise.
The wine and alcohol are charged to your Sail and Sign card and an automatic 15% is added to the bill. If you've signed on with a credit card, this will all show up on a bill the night before you disembark and if you don't have a problem with the bill, it will automatically be charged to your credit card.
I cruise the Emerald Princess, Eastern Caribbean on April 16, 2012