You can already use an iPad as Secondary extended Monitor, and now you can use Android Tablet, Phone as secondary display.
Adding Multiple monitors to your setup definitely increases productivity. But it can get all tricky without use of the right software. That’s why we had prepared a list of Best Dual, Multi-Monitor Software for your PC, Mac.
ScreenSlider allows you to utilize your Android display to extend the monitor and drag your cursor through the air rather magically from display to tablet/smartphone. All you need is a Windows PC (mac osx soon) and Android tablet /phone connected to same Wifi.
How to Install & configure ScreenSlider on Android
Step 1: Purchase ScreenSlider ($1) from the Android Market. Once installed, request a download link for the ScreenSlider desktop client by giving them your e-mail address.
Step 2: Launch ScreenSlider on your Android Tablet, phone and enter a unique device name. And on the PC, Right-click the ScreenSlider icon in the System Tray and select Find devices. Double click your device in the list once it appears.
Step 3: Next, you’ll be prompted to pair your device. Enter the code displayed on your Android in order to pair device and PC.
The app is not perfect, there are glitches and its bit laggy. However, it should improve over time.