First, some broad considerations about typographic design from Jonathan Hoefler and Tobias Frere-Jones, as excerpted from the documentary Helvetica. Followed by a description of how metal type is made from punch cutting to casting at Atelier Press. Next, how ink is made at The Printing Ink Co. in Canada, and finished off with a description of letterpress printing over at Firefly Press in Boston.
The entire process of making metal type tracks out over a few videos. You can follow all of them through on YouTube. The above one is only the first in the sequence.