potrace - Open source program that transforms bitmaps into vector graphics.
What Font Is - Find any font from any image (commercial or free)
Vector Magic - Easily convert JPG, PNG, BMP, GIF bitmap images to SVG, EPS, PDF, AI, DXF vector images with real full-color tracing, online or using the desktop app!
Font Viewer - Font Viewer is an application which does exactly that - it views fonts!
Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
AMP Font Viewer - Jump to Download - Download.