The book-selling battle on the iPhone is heating up as Barnes & Noble Monday announced the launch of the B&N Bookstore application for the popular Apple device. The free app, developed with Evryx Technologies and Spotlight Mobile, promises easy access to millions of titles, recommendations, events calendars and a store locator. It also allows users to snap a photo of a book, DVD or CD cover to get product details, reviews, and customer ratings as well as the ability to reserve a copy in the closest B&N store. An account with BN.com is not required to make a purchase via the app. The B&N Bookstore app will compete with Amazon.com's Kindle iPhone app as well as several other e-book apps including one launched late last year from startup ScrollMotion. The Street.com reported in April that Barnes & Noble is working with Sprint and an unnamed manufacturer to develop an ebook device to take on the Kindle, which Citi analyst Mark Mahaney estimates could generate $1.2 in revenue by 2010. --Mark Walsh