iOS (iPhone, iPad, iTouch)

Getting Started with iOS devices

Android

Getting Started with Android

Kindle/Kindle Reading Apps/Kindle Cloud Reader/Kindle Fire Tablet

Getting Started with Kindle/Kindle Paperwhite/Kindle DX

Getting Started with Kindle Fire

E-Ink Readers (Nook Simple Touch, Kobo etc)

Getting Started with Ebook Readers

Nook Tablet

Getting Started with Nook

Windows

Getting Started with Windows 

Mac

Getting Started with Mac

Chromebook

Getting Started with Chromebook