I found this in the Mac App Store this morning and it's $4.99. For the money IMAGE VECTORIZER works surprisingly well. I shot a quick photo of a scroll from one of my Dover books and ran it through the software and then pasted it into Adobe Illustrator. It did a respectable job of vectorizing my photo. I would avoid using it on highly shaded work as best results will probably be obtained using a simple black design like the one I chose. For quick & dirty bitmap-to-vector this is definitely worth $5.
As a reminder, vector images can be scaled to any size without degrading.

As a reminder, vector images can be scaled to any size without degrading.
