PfaEdit - A PostScript font editor that lets you create your own PostScript, TrueType, OpenType, CID-keyed and bitmap (bdf) fonts, or edit existing ones. Also lets you convert one format to another.
(description from the home page, http://pfaedit.sourceforge.net/)
Pfaedit helps people using the *NIXes to practise the subtle, slow, downright painful but nevertheless unbelieveably rewarding art of font making.
Pfaedit is, despite of its name, a font editor that supports a wide variety of font formats (Adobe PostScript Type 1/Type 3 and Apple/Microsoft TrueType and OpenType being the most important and most widely used ones). Internally it uses its own format (*.sfd, a textual format). It appears to use its own widget toolkit. It also seems to support scripting.
While it is far from perfect as of 2002-09-16 (for example, no hinting support for TrueType) and is still a teensy bit unstable (save early, save often), it is still pretty impressive in this day and age, and definitely interesting enough to check out if you're interested by font making.
The program was principally written by George Williams.
(A better review should be written some day... =( )