Is there a way to give Wordpress the queue functionality that Tumblr has? Tumblr's queue, for those who don't know, is a way to space posts out without assigning specific post dates. For example, a Tumblr queue might be set to post every four hours between 9am and 5pm. Tumblr would drop the front post in the queue at 9am, 1pm and 5pm every day. Posts are added to the queue by clicking "add to queue" instead of "publish." It's quite simple.
How can this feature be added to Wordpress?