Mixi released iPhone/Android free app Nohana [J] today.
The app is a camera application with backend photo storage web service. Every month, you get one free photobook (stamp fee 90-yen = $1 required though) made from your taking photos. The book will have 28 pages with 20 photos.
They said that their business model is to sell the second or more photobooks, such like a gift to grand-parents living remotely.
The app is seen on US iTunes Store, but the texts are all in Japanese. And the truth that the site says 90-yen mail fee only, it sounds like the free book is only available domestically.