Since Harcourt only controls the North American rights to their editions of the YW ebooks and these can't be sold outside the US, we've started bringing out international editions that can be purchased by everybody else. So You Want to Be a Wizard, Wizard's Holiday and A Wizard of Mars are out already: and now Deep Wizardry is ready to go. (The books are coming online out of order because some of the origin files have been easier to convert than others.)Deep Wizardry costs USD $5.35 and is available in Kindle / .mobi and Nook / iPad / .epub formats. More info at DianeDuane.com, or you can click here to go to the Deep WIzardry page at the DD.com shop.
(Just a note: if you've heard the scuttlebutt about a revised/updated edition of DW, be advised that this isn't it. That'll be coming out later in the year. This version matches the text of the US editions.)