bill - 4:51 am on Mar 26, 2010 (gmt 0)
Welcome to WebmasterWorld corentin.
Whatever software you're using to create the blog is adding unpublished articles to the feed. This is a problem with that software.
You could manually edit the feed and simply erase the unpublished articles. Just make sure you validate the feed afterwards to make sure your edits didn't mess up the feed.