Beer can chicken tastes awesome and very easy to do. It is definitely worth trying. Here are some tips to help the beginners:
First, I prefer to use a large diameter Weber Kettle which uses charcoal. I highly recommend purchasing the optional grill with folding edges which makes it easy to add more charcoal (you can buy it at Target for around $15). I also use the optional charcoal fuel holders which hold the coals to the sides which allows indirect heat rather than having coals under the chicken. (You can make these using several layers of heavy duty aluminum foil or use a disposable pound cake pan so long as you make several holes in the bottom & sides to allow for airflow. I put around 25-30 briquets on each side and add another 9 -10 to each side after an hour. I open the airholes on the bottom and the top of the BBQ all the way once my fire is going well and just before I put the chicken on. I put an aluminum pan under the chicken 1/2 filled with water. (You can add spice to the water, use beer, wine, coca cola, or whatever). Be sure your coals are directly under the grill's folding doors so that adding them will be easy. Make sure your grill is on a level surface.
I have done this on a gas grill with the chicken side shut off, a water pan under the chicken and an oven thermometer next to the chicken. Just make sure the temp stays at 250 with the cover down.
I use 4-6 pound whole chickens. I remove the neck & bags, wash them and pat dry. I liberally rub the essence on the chicken inside & out-it will taste best if you do this several hours before cooking. I use 3/4 can of beer (I use Bud) and add several tablespoon's Emerils Essence to each can. Consider adding some garlic or whatever suits your taste.
When you're ready to cook, sit the chicken on top of the beercan and be sure the can is in the chicken as far as it can go. The biggest problem I have had is balancing the bottom of the beercan on the grill (I usually do 2-4 at once). I wrap a piece of 18 gauge aluminum wire gently around the chickens helps balance them if I'm cooking more than one. Otherwise, you'll have to find the balance point before putting the cover on.
The grill will cook at 250 degrees once covered. Do not peek during cooking. I check the coals after 1 hour and add more coals (gently) as needed. If I am cooking multiple chickens, I may rotate them to ensure they are cooking evenly all around.
I find the chickens are done after around 2 1/4 to 2 1/2 hours. DO NOT grab the wing to see if it is done before you remove the chicken as the wings & legs will easily pull off.
Before removing the chicken from the grill, be reminded that the beer can has hot liquid inside it and that the can will not usually come out easily. Be sure to wear mitts and have another person with you with mitts on the first few times to help you do this. I recommend having one person hold the chicken while another gently twists the can and removes it. Remember that the cans will stay hot for some time. Discard the can & its contents once cool.
Test the chickens with meat thermometer before eating. They should be at 180 degrees internally.