An interesting post from the Inside Google Book Search blog today:
Today we are excited to announce the launch of a mobile version of Google Book Search, opening up over 1.5 million mobile public domain books for you to browse while buying your postage.
While these books were already available on Google Book Search, these new mobile editions are optimized to be read on a small screen. To try it out and start reading, open up your web browser in your iPhone or Android phone and go to http://books.google.com/m.