VectorMagic

With VectorMagic, a product from Stanford University, you can convert bitmap images to vector art. Just upload your image and VectorMagic will vectorize it for you.

Vectorization is the process of converting a raster image to a vector image. Raster images are pixel-based, whereas vector images are represented by geometric shapes such as lines, circles and curves.

Here I vectorized my Maria (I've always wanted to say that).