VMLite VNC Server is a free, open source, cross platform, secure, and easy to use VNC server app. You can use it to view the contents of your android phone or tablet from a desktop computer or from another mobile device.

It can work in a variety of scenarios, including from a Wi-Fi hotspot, a local area network, and an Internet connection. It can also work without the need for root on the device, but with the optional option to install the app as a server and root its internal storage, you can also run the server as a regular service.