Cheech smoking a shoulder (Boston Butt) is one of the easiest pieces of meat to cook. It is marbled with fat and very forgiving. The toughest part about cooking one is the amount of time it takes to finish.
I slather with a thin layer of yellow mustard and coat with a thick layer of dry rub. Then place it in the smoke at 225* and let it cook for 12 to 20 hours (yes time can vary greatly) until the internal temperature reaches 195-205*. The bone will pull out clean when it is ready.
Remove from the smoker and let it rest 30 minutes to an hour the pull into shreds.
Some variations:
I've heard of brining and injecting pork shoulder (but haven't tried it).
I once butterfied the butt and removed the bone to expose more meat to smoke and spice for increase bark-to-meat ration (turned out good).
You can apply the first coat of rub the night before and for a really thick crust, reapply more rub just before smoking.
You can baste every hour or not, a butt will keep its self pretty moist on its own.
Some folks wrap them in foil when they get to 170* (like I do a brisket) but I haven't tried this.
Some wrap in foil after removing from the smoker and let it rest in a cooler for a couple hours. This works well for transporting to the in-laws too.
Have fun and good luck! :D