This is one I've been meaning to do for some time, but just never ran out and bought a whole chicken to try it with. Luckily, this past month we had the privelege of receiving just that in the farm share, a fairly smallish but whole chicken. Luckily, large enough to accept a beer can.

The procedure is mind-numbingly simple. You empty the insides (luckly ours came sans neck and with a nice little baggie of giblets which we just tossed). You wash the bird inside and out, oil it with some vegetable oil, liberally apply kosher salt and fresh ground pepper, and then add a few shakes of Chef Paul Prudhomme's Poultry Magic seasoning (or, you know, if you're into mixing your own spices, then do that). Next you open your can of beer and-- this is the best part -- drink, about half of it. Apply chicken to beer can as shown in photographs:
Make various jokes. Try not to personify the chicken too much.
Get your grill hot. I have a 3 burner (front to back), so I let it get good and hot with all burners on, but then turned off the center burner, and cut the other 2 down some, I think to where the grill was holding steady at around 500 deg F. Then you just plop your chicken in there and make sure he's propped up just like he is in these pictures. Cook-- for like an hour, or you know, until a thermometer tells you it's the right temperature, whatever that is.
Unluckily in my case, I realized about 15 minutes in that my first tank of propane was empty. I was all but positive I had one in reserve. Turns out I had just a little bit left from another tank from my old apartment, enough to give me another 35 or 4o minutes of burn. At this point, chicken was crispy on outside, but just barely under recommended temperature, so we tossed him in the oven for another 15 minutes or so, and all was well.

The results are quite impressive. Very flavorful, crispy outer skin but moist meat-- the breast was just a tiny bit dry, but as long as you got a bite containing both white meat and a bit of skin it was good, and the dark meat was really really good.