FontForge

FontForge is a full-featured font editor which supports all common font formats.

Bitmap Generator

This program will allow you to generate bitmap fonts from TrueType fonts.

Bird Font

BirdFont is a font editor which lets you create vector graphics and export fonts in TTF, EOT and SVG format.

Metaflop

Metaflop is an easy to use web application for modulating your own fonts.