Submit post.content without login

Hello.
Can someone help with this problem?
I want my visitators to submit content on my website without login. Just one page on website where they can send the post.
An example will be this : http://wparchive.com/submit-theme/
I search all the base from wordpress plugin and i couldn’t find.

Someone know how to resolve this problem ? there are some plugins?

Any Information will be apreciated.

My respect.