Way to edit PDF files to include 'highlighting' circle?

Hi guys,

I've scanned several dozen pages from the local yellow pages and need to have a 'highlighting' type swirl around one of the ads (like you've just circled it). Does anyone know of a program where I can easily add one of these in? There are several businesses on the page and what I want to do is circle their ad, save a copy as business abc.pdf, then move the circle to another business and save it as business xyz.pdf to include in these sales letters..

You can use Snagit(Needs serial) or Jing(Free). Highlight/circle the ads you want with it then import the image into a PDF.