If you want the obama campaign look, you can check out this site. Upload a picture and their program will automatically change it into an obamacon like image. You can also change the text on the bottom to whatever you'd like. Pretty cool, but be warned, images are uploaded so that all can see, so don't put anything out there that you wouldn't want others to see. If you don't want to upload your own pic, you can check out the gallery of clever omabicons that have already been made.