Open posting: best practice to make a site anyone can post too

I know this may not be normal but I want to make a site that anyone that gets to the homepage can add a post (a story). I want to allow them to create an account but not require it. The posts would be monitored before going live. I haven't approached wordpress in a publicly open way before. I usually lock everything down. In order for my site to work it has to be as easy as possible to post too. Thanks