From the Big Green Egg DVD (the DVD you get with each BGE purchase)
Pork ribs are the ones most commonly referred to as ribs, but beef and lamb ribs can also be cooked in the Big Green Egg. There are several different ways to cook ribs so experiment and determine which you prefer.
Direct — Place the ribs on the cooking grid directly over the fire. This requires a low temperature (200° to 250°F) and the ribs should be turned every 15 minutes to prevent burning. Cook until the ribs pull apart easily. If you are applying a barbecue sauce to the ribs, it should be added only for the last 15 or 20 minutes as the sugar in most sauces tends to burn quickly.
Indirect – Use plate setter with legs up and cooking grid set on legs. You can also set a V-rack with a drip pan under it right on the cooking grid if you do not have a plate setter. Ribs will not require turning when using this method.
Try our way – Heat grill to 500°F. Place rack of ribs on cooking grid; close lid. Cook for 2 minutes, turn ribs; close lid and cook 2 more minutes. Remove ribs. Reduce heat to 250°F and add the plate setter with legs up; place food grid on legs. Place ribs back on grid and cook for 3 hours. Remove ribs and wrap in heavy-duty aluminum foil. Return to food grid; close lid and cook 1 hour. Brush with sauce, if desired, and serve.
Note: When using pork ribs you can buy spareribs, St. Louis-style ribs, baby back ribs or country ribs. Ask your butcher to explain the difference if you are not familiar with them.