The The Harbors of the Sun is going to be released simultaneously on July 4 in paperback, hardcover, and ebook. The paperbacks are now up for preorder at discount on Barnes & Noble and at regular price (so far) at Amazon.
Hardcovers and ebooks are available for preorder at:
Barnes and Noble, Amazon US, Powells, Mysterious Galaxy, Chapters Indigo, Books a Million, Amazon UK, Amazon Canada, Amazon France, Amazon Germany, Amazon Spain, all other Amazons, and Indiebound.
Amazon Kindle, Kobo, Barnes & Noble Nook, iTunes, Kindle UK, Kindle Canada, Kindle France, Kindle Germany, Kindle Spain, and all other Amazon Kindles.
The Edge of Worlds is coming out in paperback in March and is available for preorder at Barnes & Noble and Amazon
It's already out in hardcover, ebook, and audiobook:
Amazon US, Powell's, Barnes and Noble, Chapters Indigo, Mysterious Galaxy, Books-a-Million, Amazon UK, Amazon Canada, Amazon France, Amazon Germany, Amazon Spain and all the other Amazons. Order it locally in the US from an independent bookseller through Indiebound.
Amazon US, Barnes & Noble Nookbook, Kobo, iBooks, Amazon UK, Amazon Canada, Amazon France, Amazon Germany, Amazon Spain, and all other Amazons.