You don’t want to submit anything that you have on your site to an article directory. They will most likely outrank you for those keywords and you will get filtered. A good strategy is to use your best content for your site and create other content for article directories that specifically targets keywords and links to relevant pages on your site.
As far as submitting the same article to different directories, they don’t like that and it isn’t really that great for you. Its not that difficult to make a few changes to the article’s sentence structure and make it unique. There are even some programs that help, just make sure to always proof read.