There are more than 1000 restaurants in Beijing offering every conceivable variation on Chinese cuisine - Cantonese, Sichuan, Hunanese to name but 3. Confucius once said that you should never eat in an empty restaurant, and this is certainly true in Beijing. As far as possible, try and follow the crowds if you're after some local food, as the people of Beijing have a far better idea about what's good than anyone else.
International cuisine is offered in many places, particularly the restaurants in the larger hotels, where you can find anything from Argentinean to Zambian food if you look hard enough.
Highly recommended is the local delicacy, Peking duck, which is Beijing's main contribution to the culinary world, and one of the best places to try the dish is at the Quanjude Peking Duck Restaurant in Wanfujing.