Long overdue, I've put together a list of the available volumes of Ditko's creator owned material published by Robin Snyder and Steve Ditko over the last few years. The page is permanently linked over on the sidebar whenever you need it.
Currently nine publications are available, you probably missed at least one, so order early and often. The page will be updated if the out-of-print volumes are reprinted and when new books are announced. Subscription info to Snyder's newsletter, THE COMICS, which sees frequent content by and about Ditko, is also on the page. A post with longer descriptions of the contents of each book, as well as the out-of-print books, should be up in a little while.
By the way, I usually don't care that much about links to here one way or another, but I'd appreciate it if you consider putting a link to that page if discussing Ditko anywhere, especially his creator-owned work or his published opinions on various topics, to give people an option to go to the source.