Productivity Sauce

DRM is a nuisance, no doubt about that. After all, you should be able to use whatever ebook reader application you want to read the ebooks you've bought. If you happen to own a Kindle device, you'll be pleased to learn that removing DRM from Kindle ebooks you legally purchased is a relatively straightforward affair courtesy of the mighty Calibre ebook suite.

First step is to install the DeDRM plugin in Calibre. To do this, grab the latest version of the DRM Removal Tools for eBooks, and unpack the downloaded archive. Launch Calibre, press the DeDRM_plugin.zip button in the main toolbar, and choose Change Calibre behavior. Switch to the Advanced | Plugins section, press the Load plugin from file button and select the DeDRM_plugin.zip file. Restart Calibre to enable the installed plugin. Next, go to Preferences | Advanced | Plugins | File type plugins and double-click on the DeDRM item. Press then the eInk Kindle ebooks button and add your Kindle's serial number. Close the windows, and you are done. Next time you import a Kindle ebook into Calibre, the application automatically strips DRM off the imported file.

Source: How-To Geek