Came across this via Click on the BBC.
It is an open source Anti theft software. It can be placed on 3 machines free of charge, sufficient for most households. There are pro versions for more machines / business.
Runs in all flavours of Windows, Mac, Linux and android / iOS.
It takes less than 5 minutes to setup.
Link:
Open source anti-theft solution for your laptop, phone and tablet – Prey
Read the FAQs:
FAQ – Prey
Mike