If you have Ubuntu 10.04 or Debian Sid, then you can just use the package manager or type "sudo apt-get install electricsheep", although that will get you an old version, it should work fine.
Otherwise, the preferred way to install it is from source.
- sudo apt-get install subversion autoconf libtool libgtk2.0-dev libgl1-mesa-dev libavcodec-dev libavformat-dev libswscale-dev liblua5.1-0-dev libcurl4-openssl-dev libxml2-dev libjpeg8-dev libgtop2-dev libboost-dev libboost-filesystem-dev libboost-thread-dev libtinyxml-dev freeglut3-dev glee-dev
- install wxWidgets 3.0
- install from source flam3 (./configure; make; sudo make install), and then:
- Checkout client source and then ./autogen.sh; ./configure; make; sudo make install
It should configure itself to be your screensaver, but you can also run it from the command line just by typing "electricsheep". You can also use "electricsheep-preferences" to configure it.