Hank Shaw of James Beard-nominated food blog Hunter Angler Gardener Cook has a great photo-heavy homemade sausage tutorial at Simply Recipes. Before delving into his recipe for Italian sweet sausage, he gives advice on what special equipment to get (meat grinder, sausage stuffer, and casings) and what temperature to keep your ingredients at—that is, very cold. "You are looking for as close to 32 degrees as you can get without actually freezing the meat," he advises. He warns that your first batch could take several hours to make, but it's not very difficult overall and you'll get faster with practice.
Sausage and Law
Italian Sausage: Ever Made Your Own? [SE Talk, 2/4/09]