RasterVect - Professional raster to vector conversion program (vectorizer).
Splashroad Separation Studio - Quick and Easy Color/Shape Separation
Autotracer.org - Free online image vectorizer
ZebraTRACE - ZebraTrace is a simple tool to trace bitmap images into a pattern of curves with a variable width.
vectorization.eu - Free online vectorization tool that can help you turn black&white and colored images into a vector format.
Vectoraster - Generate custom vector halftones, line rasters and gradients