Hello, I'm a web designer by trade and I have implemented similar things. For an education solution that's free there is Ovidentia, look it up and see what you think. Otherwise you have three options, a phpbb type job where there are threads and posters just like this, a blog format where the main person starts a topic and users can post comments or a wiki type affair, I run one of these, people can post articles and all sorts in predefined areas once they have been approved as publishers, people can then edit and add at will.
Let me know what sounds right and I can point you in the right direction. All of these though will require access to a Unix/Linux server via FTP, apache, MySql and vague php knowledge (though not a lot).