The latest versions of SAS and S-PLUS (S+) can be obtained from the Software License Coordinator. SAS is free for OSU students and costs $45 per year (in 2013) for faculty/staff at OSU. Splus is free to all at OSU. Each of these applications need to be renewed annually.
R is a very good (free/open source) statistical application, which is very similar to S+. This software is available from the R project website, and can be used on UNIX, Windows, and Mac operating systems. This manual (PDF download) is a good place to start learning about R.
Other applications which can be obtained from the Software License Coordinator (see above) at COSINe (College of Science Information Network) include Stata, MATLAB, SPSS, Statgraphics, Maple and Mathematica.
Also check the COSINe website to learn about applications available on Unix/Linux servers that you can use by simply logging into the proper server and running the software from there.