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.
What Font Is - Find any font from any image (commercial or free)
Fonts.com - Fonts.com provides the biggest and best selection of high quality desktop and web fonts. Try, buy and download classics like Helvetica, Univers, Frutiger, Trade Gothic and Avenir along with popular new fonts like Soho and Neo. Find your type!
Google Fonts - Making the web more beautiful, fast, and open through great typography
Fonts Ninja - Try fonts discovered on websites in any design software
Brick - Brick is an open-source webfont service that serves fonts in their original form for high quality rendering across all browsers.