Amazon and Barnes & Noble have been quietly expanding the number of free apps available to read Kindle and Nook eBooks on any tablet, smart phone or computer. Free Kindle and Nook apps are now available for PC, Mac, iPad, iPhone and Android devices. Kindle also has a free app for the BlackBerry, as well as a Cloud Reader that makes it possible to read a Kindle eBook in any browser on any computer, tablet or smart phone.