For jerky, try to keep the temperature low.  Many will argue, but I've found the ideal temps to be 105-115.  You will need to use a curing agent, like Prague Powder #1 or InstaCure, when smoking at low temps like that.  Smokers are the perfect environment for growing botulism.  i.e. Right temps, moist, low oxygen levels, etc.  I would highly recommend buying this book: Great Sausage Recipes and Meat Curing: Rytek Kutas.  I have nearly worn mine out.  To me, it is the meat smoking and curing bible.