Vectorizer.io - Fast and easy way to vectorize an image online
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!
Autotracer.org - Free online image vectorizer
Karbon - Karbon is the scalable vector drawing application in KDE.
RasterVect - Professional raster to vector conversion program (vectorizer).
Adobe Illustrator - Adobe Illustrator is a vector graphics editor.