Allow users to create post without logging in?

the easiest way is to use this plugin: http://wordpress.org/plugins/guest-posts/

Offer your blog guests or unregistered blog readers an opportunity to post on your WordPress blog without registering themselves.
Guest Posts will help you to create a strong interaction and engagement with your blog readers.

This plugin will create a form where your guests can submit their posts.
The posts will be saved directly into your WordPress database and will show up in your WordPress Dashboard as pending.
You can then review and approve them as needed.

It will save authors Name and email as custom field, so you will be able to display authors name and give them a credit back with some simple tweaks into your theme.

You can also show a custom Thank You message after submitting the post.

The plugin is simple to install and use. Even a very novice user can install and use the plugin. And I’m sure you are good than that. 😉
No need to edit any code.
For a easy installation guide checkout the Installation tab above.

You can style the form if you wish. We have used just one class called “guest-posts”. To style the form add CSS for the “guest-posts” class and it’s sub elements into your theme.

Upcoming Features

  • User selectable category
  • Captcha validation
  • A nice Admin Panel

after installing it, create a new page and put the guest posts shortcode in it [gest-posts author=id] where id is the userid of that would be marked as the author of the posts. You can create a new user and name it Anonymous or Guest, you can just write [gest-posts].

You can create a custom Thank you page and set it via thanks attribute.
Example: [guest-posts thanks="http://yoursite.com/thanks"]
By default it will take your gusts to the home page after submitting the post.