By Aidan Malley

Published: 12:00 AM EST

Google has made its online catalog of books available in an iPhone-optimized web viewer -- but Amazon is dropping hints it will expand its previously exclusive Kindle e-books to support other mobile devices.

On Friday, Google launched a mobile Google Book Search with finger-ready navigation for iPhone and iPod touch devices as well as handsets using its own Android mobile operating system.

The move gives iPhone owners access to about 1.5 million books available in the US (and about 500,000 international books) in the public domain either through expired copyrights or open licenses, all without having to download proprietary apps.

Google's Book Search team says the feat of optimizing the collection was accomplished by using automatic text scanning to reformat the books for the small screens instead of using the raw page images. Some texts produced in difficult-to-scan formats aren't immediately available but should be added as technology improves.

The feature is a challenge to App Store software like Classics and Stanza that also take advantage of the public domain to fill their libraries but which have custom interfaces for bookmarking and navigating texts.



Not to be left out, Amazon also hinted just before the launch that it would expand the Kindle format for e-books beyond its proprietary Kindle reader to a range of different devices.

"We are excited to make Kindle books available on a range of mobile phones," Amazon spokesman Drew Herdener tells the New York Times. "We are working on that now."

Which phones will get the copy-protected books aren't known. However, the format has been built from the ground up for downloads and for viewing on relatively large screens like that of the dedicated Amazon reader, making iPhones and iPods possible (though far from certain) candidates. Paid electronic reading has become more commonplace on the Apple devices but has been curbed partly by a limited range of books to buy; Amazon, in turn, offers about 230,000 tiles, most of which are modern and are more likely to include bestsellers.

When any cellphone-ready version of the Kindle standard would appear is just as much of a mystery -- though the company is slated to hold an event on Monday, February 9th that should introduce the iPod-like second-generation Kindle and may serve as a venue for other book-related announcements.