FontForge - Free (libre) font editor for Windows, Mac OS X and GNU+Linux
Font Squirrel - Font Squirrel scours the internet in search of FREE, highest-quality, designer-friendly, commercial-use fonts and presents them for easy downloading. We don't have the most, but we do have the best.
BirdFont - Birdfont is a free font editor which lets you create vector graphics and export TTF, OTF, EOT and...
Dafont - Archive of freely downloadable fonts. Browse by alphabetical listing, by style, by author or by popularity.
FontStruct - FontStruct. Build, Share, Download Fonts
Google Fonts - Making the web more beautiful, fast, and open through great typography