Recently WordPress hosted service introduced a new featured call Post by Email. It’s like Posterous. This new feature is available for WordPress.com users. If you’re using WordPress.com, head to Post by Email detailed information.
But, what about self-installed WordPress? This feature is already in the distribution for long time ago. But, I think most people prefer posting in standard way. If you need to blog/post by email into your self-installed WordPress, I think you should try Postie. The feature is similar like what hosted WordPress users have, but of course, you need a little extra work. If you’re experienced with your self-installed WordPress, it should not be difficult to have this plugin work.