The now standard LaTeX2e system may be run with the command
latex2e
which is normally followed by a filename. (See
Getting started with TeX and LaTeX
for more details).
As the system is a developing one, it may be worthwhile looking at the
latest news files that come with the package. The current news article
is
this one.
The remainder of the news files are
There is also a short introduction to the LaTeX2e system (if you can call 93 pages short)
There are a whole host of other style options that have been contributed to the LaTeX package over the years. If what you were looking for was not documented above, chances are it is documented there. Of course, if your favourite package is not mentioned, mail ltex@ee.ed.ac.uk to tell me about it.