Just burn some wood into charcoal; you've been able to do that for a few beta versions now. :shrug:instead of ore yo can also put sand (for glass) or porkchop (for cooked porkchop) or coblestoone (for normal stone) into the upper place in a furnance.
tip: you only need 2/3 as much wood as ore/sand/porkchop/cobblesone
I think wood is better, because I have more thn enough of it, while coal is valuable and nnecessary for torches. (for far not as valuable as any ore/redtone/etc..., but more than wood or cobblestone)