The circuit simulation tutorial (http://ashwith.wordpress.com/2010/09/10/circuit-simulation-in-gnulinux-lets-begin/) looks better.
This is the getting started tutorial (http://qucs.sourceforge.net/docs/getstarted.pdf).
(8/15/2012;)
Qucs is an integrated circuit simulator which means you are able to setup a circuit with a graphical user interface (GUI) and simulate the large-signal, small-signal and noise behaviour of the circuit. After that simulation has finished you can view the simulation results on a presentation page or window.
$ sudo aptitude install qucs
The following NEW packages will be installed:
freehdl{a} guile-1.6{a} guile-1.6-libs{a} iverilog{a} libfreehdl0{a} libfreehdl0-dev{a}
libguile-ltdl-1{a} libqt3-mt{a} qucs verilog{a}
0 packages upgraded, 10 newly installed, 0 to remove and 39 not upgraded.
Need to get 14.6 MB of archives. After unpacking 43.2 MB will be used.
Freedom, World peace in unity! 