De-Pixelize Your Images with VectorMagic

Web site VectorMagic turns virtually any image into vector art that can be resized as much as you want without any nasty pixelation—perfect for creating your scanned signature, for example. The site is free and simple to use, but for a bit more detail check out their howto introductory video. Whether you are trying to perfect your scanned signature or you've got a logo or design you want to be able to resize indefinitely, VectorMagic will do the trick. VectorMagic can be used on photographs to interesting effect, but count on losing some detail.

http://vectormagic.stanford.edu/