timlinden

Remembering to post every day, and which days you already posted, is super easy with this plugin. 
It shows you a calendar with days red when there isn’t a post, and days green when there is. Green 
days you can hover over and see the title of the post, and click to edit the post for that day.

wpFutureCal

A simple calendar that displays when you edit posts, showing which days you have posted on.

Ryan

Aelora

Make it easier on yourself to schedule future posts.
Auto Future Date allows you to quickly and easily schedule posts based on the 
last post on your site. A simple click on a link and your post will be scheduled 
for a future date based on a set of simple rules that you set up.
I use this on a blog of mine where I write several posts at a time and want to 
spread them out rather than publishing them all at the same time. Future posts 
are great for this, but I found myself going back and forth to the calendar 
to schedule.
When activated the plugin adds an “Auto” link right next to the link that you 
use to schedule a future post. Clicking on the Auto link makes an Ajax call that 
will set the date for your post at some point in the future, using rules that you 
set.
More information at <a href="http://www.nutt.net/tag/auto-future-date/" rel="nofollow ugc">Nutt.net</a>

Auto Future Date

Adds an "Auto" link to your post page that will automatically schedule your next post based on the most recent post.

wpFutureCal vs Auto Future Date