I'm added my books to a number of different ebook stores but I have to say that CTR does the best job of supporting it's indies authors.
They send out post like below to their readers and let them know when your book go up on their site.
KarenneLyn is very helpful and makes you feel as if you are a valued member of the CTR team.
Take a good at their site and see what you think.
I'm sure KarenneLyn would love to help you add your books to the site.