You can usually get big slabs of pork belly from local pork producers at your farmer's markets, or any decent butcher can order you one. You do need some curing salt No. 1 for this recipe, which you can buy online. Once made, this will keep about 2 weeks in the fridge, and indefinitely in the freezer.
Smoke the bacon over the wood of your choice. I try to keep the smoker as cool as possible because you don't want to fully cook this bacon; less than 200 degrees Fahrenheit is ideal. It is supposed to be very smoky, so go for at least 4 hours. Remove it from the smoker when it's as smoky as you like, then let it cool to room temperature before putting it in the fridge or freezing it.