Well, its always a good idea (and recommended) not to submit the same article that you have on your website to other article submissions sites. I usually rewrite some portions of a particular article before submitting it to avoid duplication, but I cannot recommend this to you, since rewriting may become tedious and boring, thus you loose interest in this area. I would recommend what scottwood1986 had said, but again, it would be more safe that you edit at least some portions of your articles. My motto, always be on the safe side