Overleaf is an online LaTeX and Rich Text collaborative writing and publishing tool. You can use a free version with storage space up to 1GB and you find a whole string of templates for different publishers.
https://www.overleaf.com/
ShareLaTeX is an online and collaborative LaTeX editor. The free version includes only one collaborator.
https://www.sharelatex.com/
There is a free online course on LaTeX by John Lees-Miller available. It was held at Bristol University:
https://www.writelatex.com/blog/7-free-online-introduction-to-latex-course-part-1#.VClLmhD9yLt
WriteLaTeX is a tool to write papers collaboratively online:
A new introduction to LaTeX entitled LaTeX and Friends by Marc van Dongen has been published. The e-book is available at http://dx.doi.org/10.1007/978-3-642-23816-1 [only for subscribers]. A YouTube promotional video shows what you can do with LaTeX.
More available ebooks [only for subscribers] about LaTeX:
Die neue deutschsprachige LaTeX-Einführung Wissenschaftliche Arbeiten schreiben mit LaTeX von Joachim Schlosser liegt nun im Neuerwerbungsregal der Bibliothek bereit.