I've done a dozen online book discussions using Moodle (and Blackboard) with 4th-6th graders. Is that young enough? I can't see why primary students couldn't use it. Let me know if you need more info, I have mixed feelings about the book discussion format, but found Moodle easy to set up and the students found it easy to use.
Have you seen Mary Cooch's book "Moodle 1.9 for Teaching 7-14 Year Olds"? It just came out a few months ago. It is well written, easy to understand, and has good ideas for using Moodle with younger students.
We have a teacher in our school district who teaches a 2-3 class and is so successful using Moodle. If you have a contact address, I can send her name your contact information. She teaches in the Brownsburg Community School Corporation in a suburb of Indianapolis.
Sure, I will. I am trying to learn as much as I can on tech to see "what" I can use with young students, especially with world languages. My students are very young (PreK to 3rd), so it is difficult -at least for me- to use tech in the classroom other than games.