Ironman

One of my all time favorite cooking materials is cast iron. It's cheap (relatively), it's almost indestructible, its easy to clean and it's heat retention properties are unmatched. Additionally it is very versatile, after leaving home my first set of pots and pans consisted of a 2 quart cheap saucepan and a cast iron chicken fryer (a deep frying pan with a lid) and with it I could fry, deep fry, sear, bake, broil, roast or braise (stove top or oven). The only thing I used the saucepan for was to boil, stew or steam.

Seasoning Cast Iron:
Do this before you cook anything on the cast iron. Even if the cookware is 'pre-seasoned' I still do it.

Wash the cookware with hot, soapy water and a stiff brush. (This is the ONLY time one uses soap on cast iron). Rinse and dry it completely. Apply a thin, even coating of solid vegetable shortening to the cookware (inside and out). Place aluminum foil on the bottom rack of the oven to catch any dripping and set the oven to 350°.  Place cookware upside down on the top rack of the oven. Lids (if any) go right side up. This is so no fat pools on the cookware- pooling fats will cause a sticky mess that requires a sandblaster to remove.  Bake the cookware for an hour.  After the hour, turn the oven off and let the cookware cool in the oven. In the future if you notice the seasoning wearing, just repeat the steps.

Cooking With Cast Iron:

Cast Iron has the best heat retention of any cookware I know of. When one places cold food in a hot pan, the pan looses some of its heat to the food- there by cooking it. Cast Iron looses little to the food so it keeps a high temperature. Because of this a lower heat is needed and I seldom cook with cast iron over anything higher than medium. Additionally its heat retention properties allow for good searing and browning of meats. This combined with its ability to regulate fluctuating oven temperates make cast iron ideal for long low braises like pot roast. You brown the meat in it on the stove top, add liquid then put it into a slow oven for a long, low braise.

Cleaning Cast Iron:
Rule #1: Do not use soap.
Rule #2: Do NOT use soap.
Rule# 3: Do not put it in the dishwasher (See Rule #2)
  The trick is to clean the cast iron while it is hot, preferably as soon as you are done cooking in it. Other than that you only need two things to clean cast iron; water and a stiff brush. I use a natural hog bristle brush because I am afraid a synthetic bristle will melt on the hot iron.
  As soon as you evacuate the food from said cookware, transfer it to you sink. Turn the water on the cast iron, there will be steam- a lot of steam- so be careful. Scrub it clean with your brush. If extra scouring if needed I usually drain off the water and add a few heavy pinches of salt and continue to scrub away, this trick is very handy for cast iron grill pans. Please note that if you were cooking on high heat let it cool down or you run the risk of warping or cracking the hot iron. I can't think of why you would be cooking on high with cast iron though, to brand cattle maybe?
  After it's clean move it to the stove and heat it until it's dry. Drizzle a bit of cooking oil into the hot cast iron and spread it with a folder paper towel. The more you use it the easier it becomes to clean because the seasoning improves with use. Because of this shy away from high protein 'sticky' foods like fish and eggs until the cast iron is well seasoned.