Training for embedded Linux and Android

At the end of one of my training courses recently we got into a discussion about how to continue working with the code and configurations developed during the course after everybody had gone home and they no longer had a target board. I said, you could use qemu to emulate an ARM target that is rather similar to the one we actually use. Thinking about it a bit more, I realise that the situation is general and common enough to be useful to many people (or so I hope) and so I have written this tutorial.