You can also use Photoshop to actually trace and create a path. Use the magic wand to select the form you want as a path, create a new working path, save that path and then -> Export -> Export path to AI. Depending on what you want, that is. I'm sure you're aware that you'll never get 'perfect' vectorised graphics from any such process, right?
In the olde days, Adobe had an application for it, called Streamline. I sometimes miss that one... *sigh* (might still be able to find it and run it in Classic, though...).