Daily Doodle
National
Parfait Day
National
Blasé Day
Here's a company that will design a cover for your self-published book for $249. They even have a downloadable pdf on book design.
A blog about book cover design, with a page of favorite designs, and ideas.
An interesting before and after comparision of covers and their affect on sales
AIGA Award Winning Book Covers: “50 Books | 50 Covers”
And a search for “Book Cover Design” on Pintrest