In the beginning letterpress classes at San Francisco Center for the Book, we teach typesetting the old fashioned way — with metal type, letter by letter. It’s a good introduction to press work, but in practice, almost anyone doing letterpress these days typesets on the computer and then gets a plate made. Some advantages are that you can use any font on your computer, incorporate illustrations, and proof-reading happens before you ink up the press. Erica at Three Red Hens has a nice set of blog posts about the process of creating and printing one of her illustrations from plates (that’s a detail of one of her cards on the right).