Apparently this is a very practical function for illustrators, but if you just have an iPhone around you instead of a computer with ColorDraw. VectorPro iPhone app can help you turn photos into vector images.
VectorPro is an easy-to-use design app developed by Orawee Wiriyathananon. The iPhone app can automatically trace the edges of patterns, and convert the whole photos or graphics to vector images that can be edited through illustration softwares like Adobe Illustrator and ColorDraw. Of course, for the simple iPhone app, those simple hand-drawn sketches may be more easily converted to ideal vector images. Apart from that, the latest version has also integrated Dropbox sync function. This means you can upload your great works to your Dropbox account.
VectorPro with a size of 2.5MB is compatible with iPhone, iPod touch and iPad running iOS 3.0 or later. At present, the iPhone app is available for free. If you’re interested, jump to App Store for more details.