Google Play Books allows you to publish ebooks on the Android platform via the Google Play Store. They can also be linked to corresponding print or PDF titles.
To publish on Google Play you need a Books Partner Center account. Go to play.google.com/books/publish/ to get started. You can use an existing Google account or create a new one. Then choose your publisher type:
Books Partner Center
Once logged in you'll see the Partner Center interface. New titles can be added in the Book Catalog section, but first you'll have to set up your payment profile.
You might find the tax information for non-US authors useful at this point.
Add A New Book
In the Book Catalog section choose Add Book:
First, you'll be asked if you want to sell the book on Google Play, or offer a preview only:
Then you'll be asked to select a Book ID by supplying an existing ISBN or allowing google to generate an ID:
You can then provide the book information by working through the book info, content and pricing sections: