Cast iron has a melting point of around 2100 degrees Fahrenheit.
A benefit of cast iron is that it is near indestructible under normal uses. If you have a piece of cast iron that needs to be cleaned because it is rusty or it's surface has large pieces of carbon on it, you can either scrub it down to a fine surface or burn it. When cleaning with a flame, be careful because it is possible that your cast iron can warp or even crack (so I am told--I believe I warped one pan). Try to keep the cast iron evenly heated by rotating it and do not put it in a fire hotter than it needs to be. Burning will leave you with a very clean piece of cast iron.
Curing cast iron is the process at which a layer of oil is transformed into a more permanent protective layer. When oil is applied to iron and baked at high temperatures, it will solidify. Oils that are solid at room temperature work better. Thus Crisco is a good choice, although many people praise lard.
Most sources will tell you to cure cast iron cookware at 350 degrees Fahrenheit for a few hours. However, this often leaves a brownish finish to the cookware. If you would like to blacken the cookware faster, a higher temperature is needed (450-550 degrees Fahrenheit). Since baking greasy iron at 450-550 can yield a lot of smoke, I cure my cast iron outside in a propane grill. Bake the iron at a high temperature for up to an hour, and then let it cool while remaining in the grill.
Also, two thin coatings are far superior to a single thick coating. Thick coatings tend to cause the oil to run and become thin in some areas and thicker in others, creating a goopey and uneven appearance. A good way of ensuring a thin but universal coating is to apply the fat liberally, place it on the grill for a few minutes to let it heat up, and then wipe off the excess with a rag or a paper towel.
Once you have cured your iron, your job is not done: it still needs to be seasoned. Seasoning involves cooking with oil and properly cleaning your cookware. For the first few uses after curing, cook something greasy like bacon. A pan-seared steak will also leave behind a wonderful oily layer, despite some of the meat sticking (it should easily scrape off). If your cast iron is properly maintained, your cookware's non-stick quality will improve with time. Do not clean it with soap, instead use a gentle scrubber for stubborn bits of food and wipe down the surface with a rag. You should store your cast iron with a thin layer of oil for protection.
Pieces of cast iron are rather inconveniently measured in numbers that do not seem to correspond to measurements. For example, a number 9 Griswold dutch oven holds 5.5 quarts.