I say 'officially' because I sat in the Glasgow Waterstones last week signing a couple dozen copies of the Nova War paperback, but technically the release date of both that and the hardback of Empire of Light, the third Shoal book, is today, July 2nd. Both look like they're doing well on Amazon. Haven't seen any reviews of Empire of Light out in the wild yet, but my eyes are peeled.
There's an excerpt from Empire of Light here. If you want to find an easier way to read it, I'd recommend using either the Safari browser's reader function or, if you're like most people I know and use Firefox, there's a Firefox add-on called 'readability' which provides a very Safari Reader-like function. Both make reading long-form text on the screen a much more pleasant experience.
Edit: the ebook of Empire of Light should be out on the 6th of August, according to Pan Macmillan/Tor UK's own page. I'm guessing it'll appear on Amazon.com and other sites that sell ebooks shortly after.