Can Wordpress allow me and a friend to work together on a single blog?

Can I do that without using wordpress MU because I'm pretty sure it is a lot different.

Public Comments

1. If you want he/she to have the same rights as you set up their account as an admin account How to Allow Others to Post to a WordPress Blog http://www.ehow.com/how_2004938_others-post-wordpress.html
2. Yes, you both can work on the blog together. There are certain user roles that you can assign that will restrict or grant access to certain parts of the blog. If you don't want someone to change the themes, or edit the plugins, you can control that. Check this out for Wordpress Roles and Capabilities from the Wordpress Codex: http://codex.wordpress.org/Roles_and_Capabilities