Duplicate content – multiple URL with the same content and identical home page with the same content. The penalty applied to "duplicate" sites is that only the original version of the page gets listed in the search engine and the duplicates content don't get listed at all.i have just got a information from a discussion forum on the dupticate content and want to share with you.
www sitepoint com/blogs/2009/03/07/seo-for-google/