Vector Magic desktop edition is now available. It can convert bitmap images into vector images, with fairly impressive results. You can tweak the settings throughout, and it’s a useful tool if you need to do this sort of thing. Much easier than hand-tracing scans of logos and the like!
Here’s one I prepared earlier. I think I’ll tweak the right eye, but otherwise it looks pretty good. It’s much easier to make the background transparent if you don’t have to worry about anti-aliasing, too.
For reference, here is the original image, scaled to about the same size. Pixellated, a bit!