Software engineer and author Deirdre Saoirse Moen has built a handy web-based royalty calculator that can tell you when each of the major ebook distributors and ebookstores will pay and how much they'll pay based on the number of titles sold.
An author can select a retail price from $01 to $19.99, a sales quantity from1 to 10,000 copies, and then choose which of 7 ebookstores and distributors sold what percentage of the titles.
The bottom of the page shows how much each of the 7 sources will pay, and when you can expect that payment.
It doesn't cover the compete market (Ingram, Createspace, and the specific Kindle Stores aren't mentioned, for example), and it doesn't take into account the delivery fee that Amazon charges or the intricacies of which Kindle Stores offer the 70% royalty option in which markets.
But in spite of the issues I think this tool is still a useful way to double check which ebookstore pays how much. I think it's worth book marking and coming back to.
Have you tried it yet?