The basic concept is a markup language like turbocharged HTML, but it also includes easily organized documents with sections, subsections, indexes, and tables-of-contents.

Although there is a learning curve, I've found that I do almost all of my technical documentation in LaTeX and it's been for me by far the most efficient way to do it. I've had some peers scoff at the concept because they've never heard of it or used it or have heard it's difficult to learn (not more than HTML in my experience), but I've also known other people who use it for the same thing I do, and they absolutely swear by it as well.

It also supports easy export to HTML (latex2html, written in Perl), PDF (pdflatex), PostScript (dvips), and other formats, and produces the most visually consistent and readable documents of any documentation system I know.

If you are using GNU/Linux, you can find the tetex (the Linux version of LaTeX) RPMs at http://www.rpmfind.net/linux/rpm2html/search.php?query=tetex.

They also come on the Red Hat installation CDs.

If you decide to investigate it and have any questions, send me an e-mail. I'd be happy to give you some pointers to get you started.

Hope this helps :-)