Look for what's called a Boston Butt, a big blocky cut of pork from the top of the front shoulder of the hog.   Butts weigh between 7 and 10 pounds and currently run around $1.75 per pound.  They often come in a cryovac two pack (might as well cook two, the cooked meat freezes beautifully should there be left-overs). 

They'll have a blade bone in them, which I prefer over boneless versions because the cut stays together and is easier to handle.  Each butt should also feature a big cap of white fat on one side, which will baste the meat as it cooks and what's left will be tossed when you prep it (fat is gooood). 

Figure about 3/4 of a pound raw weight per person - a 10 pound butt will feed about 15 adults (the meat will lose half its weight from water, fat and bone).

Pre-heat your cooker be it a; gas grill; charcoal grill; bbq pit; oven; or (gasp) crock pot.  The oven and crock pot will work fine, but will give you no smoke flavor and the crock pot will become a soup of rendered fat and it certainly will not solidify your reputation as a BBQ genius.

While the cooker heats, season your butt (the pork butt)with a rub and you're good to go.

Boston butts require a long slow cook to break down the connective tissue, expect 7 to 10 hours at 225 to 275 degrees (the higher the temp the shorter the cooking time).  Check out newsletter #6 for a discussion of basic BBQ set-up (indirect cooking) and technique.

If you're cooking outdoors, as you should be, throw some wood on the fire and keep a steady stream of smoke going.  After several hours, when your coals are died down, feel free to finish the shoulder in the oven.  Simply wrap it in foil, put it in a pan and set the over for 225 degrees.  When the meat is pulled back from the bone about a half inch and fork sinks into the meat easily, your done (see picture of exposed bone below). 

Let the meat cool for about a half hour before attempting to prep it.  Prep it in a big roasting pan to catch all the fat and mess. Use your hands (gloves are nice) to break the meat apart and strip off the nice soft fat.  Chop it and serve up.  Heavenly pork.

Have any questions?  Shoot me an e-mail and I'll help you out.  Kirk