potrace - Open source program that transforms bitmaps into vector graphics.
Fonts Ninja - Try fonts discovered on websites in any design software
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!
What Font Is - Find any font from any image (commercial or free)
Autotracer.org - Free online image vectorizer
Adobe Capture - Turn any photo into a color theme, Look, vector graphic, or unique brush that you can use in your creative projects with Adobe Capture.