This article is from the Amiga FAQ, by Ignaz Kellerer with numerous contributions by others.
This is very, very difficult. Many people imagine that there are programs that will simply convert pictures into fonts for them. This is not the case; most fonts are painstakingly created by drawing curves that closely approximate the letterforms. In addition, special rules (which improve hinting, etc.) mandate that these curves be drawn in specific ways. Even designing, or merely digitizing, a simple font can take hundreds of hours.
The easiest way of learning how to create fonts, is to have a look at existing fonts and try to change some letters.
Given that, there are two major programs used for font design on the Amiga, TypeSmith 2.5 ($150) and FontDesigner ($100). These programs will allow you to import scanned images, and then trace them with drawing tools. The programs will then generate Adobe type 1, 3, TrueType, AGFA Intellifont, DMF and Bitmap fonts for either the Amiga, the Macintosh or the IBM PC. They will also generate automatic hinting. They also open previously constructed outline fonts, allowing them to be modified, or converted into another format.
As far as I know, there are no shareware programs that allows you to generate outline fonts.
There are also two programs for creating bitmap fonts. Personal Fonts Maker and Calligrapher. The second one has not been updated for several years, but it still is a good tool to work with. The first Program was created by adding some features to a good bitmap paint program (Personal Paint).
There are some shareware tools to create bitmap fonts which you can convert to outline (vector) fonts with TypeSmith.