SPSS for Unix is not installed on stat network. If you would like to use it, you can either use SPSS on vet.ruf.rice.edu or request a copy for your PC. Like SAS, the license for the PC version of SPSS need annual renewal. Rice also has site license for Systat for windows.
Minitab is often used for undergraduate courses. It is pretty simple and you can learn it quickly with the students if your TA duty requires you to do so. Minitab works only under DOS/Windows and there is no site license for it. Ask your professor or Diane if you need a copy for your TA job.
The GAUSS Mathematical and Statistical System is a flexible and powerful programming language that provides a wide variety of statistical, mathematical and matrix handling routines. It has over 400 functions built-in, including EISPACK and LINPACK ( another word for speed) routines which means you can make your simulation run much faster than S-Plus counterparts. Gauss is available on vet. You can start gauss 3.2 with command gauss. A terminal only version of gauss 3.4 can be started with command tgauss.
BUGS http://www.mrc-bsu.cam.ac.uk/bugs stands for Bayesian inference Using Gibbs Sampling. It is used to analyze complex statistical models using Markov chain Monte Carlo (MCMC) methods. Its windows version (called WinBUGS) can be downloaded from its website for free (you do need to register) and its Unix version (called ClassicBUGS) is installed on stat network. Please refer to its online document for using classicBUGS. It is a pity that classic BUGS has not been under development for quite a long time and stays at its 0.7 version while WinBUGS is on version 1.3. As a direct result of this, classic BUGS and WinBUGS have a slightly different grammar and totally different usage. You will feel the inconvenience when you are forced to port your WinBUGS code to classicBUGS when you need the power of Unix for your simulation.
gnuplot is a useful program to generate high resolution figures from your data. It is free but has nothing to do with GNU project. It might not be worthwhile to learn gnuplot to interactively plot your data, ( S-Plus can do this beautifully, though more slowly). But if you are writing your programs in C or Fortran, gnuplot is the easiest way to incorporate graphics ability into them. This approach has been used by many small statistical applications like GeoStat.