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.

maximevalette

contemplate

With the iCal Feeds WordPress plugin you can have an iCal feed to have your blog posts 
(past and future with a customizable secret parameter) in your favorite iCal software: Google Calendar, 
Outlook, Hotmail, iCal, Evolution…

iCal Feeds

Generate a customizable iCal feed of your present and future blog posts.

wpFutureCal vs iCal Feeds