Google has announced that it plans to take on ebook readers such as Amazon's Kindle and Sony's eReader with the launch of a mobile version of its Google Book Search service.

From today, users wanting to read any of the 1.5 million books currently available on the service can now do so by visiting a mobile friendly version of the site that has been optimised for all mobile phones, but in particular the Apple iPhone and the Google backed G1 Android handset from T-Mobile.

"If you use Google Book Search, you'll notice that our previews are composed of page images made by digitizing physical copies of books. These page images work well when viewed from a computer, but prove unwieldy when viewed on a phone's small screen", Viresh Ratnakar, Guillaume Poncin, Brandon Badger, and Frances Haugen, of the Book Search Mobile team said on one of the company's blogs, explaining why we haven't seen a mobile version before.

The system uses OCR (Optical Character Recognition) software to scan pages so that they now "flow on your mobile browser just like any other web page".

Far from perfect however, the search engine giant is warning that the free books might not be completely perfect:

"If you do bump into some rough patches where the text seems, well, weird, well, you can just tap on the text to see the original page image for that section of text", the blog post states.

The eBook reader market is heating up over the last 12 months with Amazon expected to launch a second version of its ebook, the Kindle, this month. Analysts predict that the online retailer sold over 500,000 in 2008.