In the past I have written about Tween and Teen Tribune. You can read more about them here. These sites provide news stories for students. Teachers may setup student accounts that allow them to leave comments that are moderated by the teacher.
Tween Tribune just released Tween Tribune Junior for grades 1-3. It includes all of the same features as the other versions! This is a great resource for integrating primary source documents, current events, collaboration and student publishing into your classroom.