Google has made the original text of 1.5 million books available for free via iPhone or Android-based devices, reports The Telegraph. The report cites a Google spokesman commenting that “we believe we’ve taken an important step towards more universal access to books.” Google’s Book Search for mobile offers free books that are out-of-copyright.

The move appears to be a direct threat to Amazon’s Kindle e-book reader, which was well-received upon launch in the US last year. The Kindle currently runs on Sprint’s EV-DO network, but is rumoured to be set for an update later this month with release of Kindle 2.0. Other companies involved in the ‘mobile books’ space include Vodafone, which last year launched a service to bring audio books to mobile phones.