Any real hardwood charcoal will work, just not briquettes that are held together with bonding agents. Even chunks of dry wood will work, you have to keep them around the edge to start to char before moving them into the center as fuel. That method isnt as good, but it works, and it works great to extend to life of the other charcoal. You can also make your own charcoal easily.. burn some wood but douse it once its all pretty charred (ex: campfire cook your meals then douse it). Hose it off to clean the ash etc and let it dry, voila. I personally use propane now, but I really enjoyed my charcoal forge.
You can also use bituminous blacksmith coal, which is a stinky alternative. It works great, gets very hot.. but the fumes are terrible, and impurities can be bad in some cases. Still, both methods have been used as long as history almost, and both work. My second forge was coal, and made from a wheel hub.. it worked alright, but I preferred the charcoal forge.
If you use charcoal, check out Tim Lively's webpage, he has his washbasin design on there. I would use a metal pipe with holes drilled rather than a pvc pipe (will melt) if you use Tim's design. My first forge was this design, and I enjoyed it.
A hairdrier (cold air mode) works just great.. or you can get an old hand cranked forge blower at a swap meet/garage sale/flea market. You can buy new ones too.. but you don't want a TON of airflow, or it will get too hot or not work if it gets too high. I used a blower from a honda accord for a while, hooked to a battery charger for power.
A word of advice, if you use coal (and possibly charcoal, though I hadn't had the problem) be careful not to get it too hot. It will EASILY melt your hard work in a very short time if you're not careful. Depends on thickness of metal of cours
