Google announced the launch of a mobile version of Google Book Search, opening up over 1.5 million mobile public domain books in the US, and over half a million abroad, in a bid to compete against Amazon's Kindle eBook reader.

The books were previously made available free on PCs are now accessible on mobile devices like the iPhone and the T-Mobile G1.

Coincidentally, Amazon also announced it was working on eBooks that work on its product Kindle, available on a variety of mobile phones. The company, which is widely expected to unveil a new version of the Kindle next week Monday, did not say when Kindle titles would be available on mobile phones.

Google used Optical Character Recognition (OCR) technology to transfer the scanned book pages into screen friendly text for iPhones and T-Mobile G1s.

To access Google Mobile Book Search, users can go to