I found the XBMC auto-updating capabilities severely lacking, as a result, only raspbmc is supported (openelec has no way of installing the required lxml package).
To use on any linux system, ensure python's lxml and requests are installed.
- install and start raspbmc
- select "Exit" from the shutdown menu
- when prompted, press ESC for a terminal
- login as "pi", password "raspberry"
- type in the following command wget -O- http://mbr.github.io/xvisi | sh
- wait for a reboot and enjoy
Unsupported and not-up-to date: https://raw.github.com/mbr/xvisi/gh-pages/repository.xvisi.zip