Article-Submission Plugin

I would like to install a function like the one here…

http://www.lucianne.com/postnew.asp

… that allows people to register on my blog site and then post the title, link and first paragraph of an article, plus a comment, and then for others to put their comments below and have the whole thing display essentially like this:

http://www.lucianne.com/threads22.asp?artnum=387864

Thanks.