To use SLaTeX as a standalone program, either drag your ".tex" file onto SLaTeX (under Windows or MacOS X), or type slatex file in a command shell.
In addition to the SLaTeX tools, this collection contains a parallel set of PDF-SLaTeX tools, which are identical except that they call pdf-latex rather than latex. In particular, there is now a launcher called (PDF-SLaTeX/pdf-slatex).
NOTE: in order to run slatex, your TEXINPUTS environment variable must contain a reference to the directory in which the most recent version of "slatex.sty" lives. That file resides by default in the "slatex" collection of the main installation.