LaTeX guide half-done, published anyway
A while ago I mentioned I was planning to write an introduction to LaTeX. Since then I have, while not actually finished that document, at least produced the skeleton and included all of the topics covered in my original notes-to-myself as well as some useful fundamentals. I don't recommend using it as your sole source of information, and it will probably make LaTeX purists wince in some places, but it admits where it's incomplete or doubtful.
An Idiosyncratic Guide to LaTeX
(Append .pdf or .tex to that URL to specifically get the rendered or source formats.)
As you can see, I decided to write the guide itself in LaTeX, primarily for the sake of including examples (not that I've done much of that yet), but also so that it is self-demonstrating. I considered changing the page size so that it has no page breaks at all, for better on-screen reading, but that would prohibit the use of footnotes. I've considered using margin notes instead, but they would require a large margin which can also be annoying on-screen. Please let me know what you'd like to see for such formatting.