Not much of a recipe Dan ... put the sausages in a skillet with a tight fitting lid, add 1-2 cups of water, bring to a boil, reduce temp to low, put lid on pot - simmer about 10-15 minutes turning once ... then remove, skin, then fry up.
RE CASINGS: You can get natural casings that are kosher (sheep and cow). There are several sources for sheep and cow casings but I don't know if they are kosher certified. Check with a kosher butcher or meat market if you want the kosher certified casings. They can order them for you if they don't carry them.
"It ain't what you don't know that gets you in trouble. It's what you know for sure that just ain't so." - Mark Twain