iDisplay for Android, and other variants are available, effectively turns your smartphone into a companion screen to a main PC or Mac computer.
The application comes with a charge but the experience perhaps deserves this. Regardless of whether you are using a flavour of Windows or Mac OS X it lets you expand your desktop to your handset and control and access files and software from there simply by dragging them over.
The developers claim that it is 100 per cent compatible with all Android devices on the market, whether they be tablet or smartphone. It will require Android OS 2.1 or later.