Method 1 - Using Hashish
a) What you need depends on the quality of oil you want. I usually use high quality isopropyl (read NO rubbing alcohol) for straight run oil, and good hash that hasn't been pressed with any crap to increase the weight and decrease potency.
This is the case with most of the hash that is consumed in countries other than the one it was produced in, it tends to get "diluted" the further it travels. If you are not sure of the hash quality, don't try to make oil, it isn't for novices. Don't throw your money away.
Another thing to consider is quantity. One gram of hash oil will take several grams of hash to produce, and even more for honey oil.
Crumble the hash into a pot, pour in some isopropyl and heat it for 30 minutes. Get some high quality filter paper and filter out the gunk. Evaporate the alcohol and there you have it. For extra purification you'll need some petroleum ether (best). General ether purification as follows.
Mix a solution of resin/isopropyl with some ether and water, then gently tip the container upside down and back. Do this about 20 or 25 times and let it stand until the layers separate (water/isopropyl with ether on top).
Siphon or pipette the ether solution off and repeat 2-3x with fresh ether. Evaporate the ether (try to salvage it if possible) and voila - smooth killer oil (If you used good hash and didn't fuck up!).
Be careful with the ether though, it's very explosive, sometimes spontaneous when it decomposes. You can go further and make honey oil with activated charcoal and very high quality filter paper but you tend to lose a substantial amount. It's usually worth it though.
B) I have heard that you can wrap it up with dry ice in some newspaper and scrape it off the paper when the ice dissolves. Also, I was told that if you put your weed in a filter and pour hydrogen peroxide through it into a pot of water and boil it down it will produce oil.
Method 2 - Using Marijuana
Porcelain pot or heat resistant pyrex bowl, one which is suitable for use in the oven.
Cast iron skillet (frying pan larger than the porcelain pot)
Coffee filters (the re-usable gold filters work very well as well, these can be bought at supermarkets)
Isopropyl alcohol (commonly available at pharmacies, look for alcohol that is 99% pure, denatured alcohol also works well, sometimes isopropyl alcohol is called rubbing alcohol)
Take 1 coffee filter, and place your marijuana in it. Pour the alcohol over the marijuana in the coffee filter so that the alcohol drains into one of the bowls. Squeeze every bit of the alcohol from the marijuana into the bowl.
Now transfer the same marijuana into a clean coffee filter, and use the same alcohol to pour over it again into the second bowl.
Keep repeating this over and over again. If you have a problem with the coffee filters breaking apart while you are squeezing the marijuana, use 2 or 3 coffee filters at a time. The alcohol will turn green.
Next, take the iron skillet set it on the stove, and put the porcelain pot into the skillet. Fill the skillet with water.
Alcohol is extremely flammable. Don't be stupid, be CAREFUL!
Do not cook the alcohol over the open flame. The water in the skillet assists in preventing the alcohol from getting too hot and helps to prevent the alcohol from igniting on fire.
Ensure your kitchen has good ventilation. Use the stove fan and other fans to move the air around in order to prevent fumes from gathering in one place and igniting.
Let the alcohol in the porcelain pot in the skillet simmer on LOW. Make sure the skillet remains full of water. The alcohol will evaporate very very quickly.
Make sure you do not let it evaporate too quickly or burn the alcohol.
Once all the alcohol has been evaporated off, you will be left with hash oil. Take a razor blade and scrape it up and smoke it.