Latex: LaTeX is a high-quality typesetting system, with features designed for the production of technical and scientific documentation. LaTeX is the de facto standard for the communication and publication of scientific documents. David R.Wilkin's primer "Getting Started with LaTeX" is a good tutorial to getting started with LaTeX. For those who have to live with a WYSIWYG documenting tool, check LyX. This is a front-end for latex. It isn't as powerful as latex proper, but helps with a good WYSIWIG.

Lout: A document formatting system similar to latex. Good features, documentation and history. Light weight and outputs postscript. Thanks to Emiliano Gavilan for this link.

Abiword: As the AbiWord home page says, "AbiWord is suitable for typing papers, letters, reports, memos, and so forth". It has won many awards and seems to be the best open source WYSIWYG word processor. Check out the above link to know more about it and download it.

kword: As the kword home page says, "KWord is a FrameMaker-like word-processing and desktop publishing application. KWord is capable of creating demanding and professional looking documents. Whether you are a corporate or home user, production artist or student, KWord will prove a valuable and easy to use tool for all your word processing and layout needs". Check out the above link to know more about it and download it. (you might want to know more about the whole koffice suite).

KPresenter: KPresenter is the presentation tool of the KOffice suite of office utilities. It allows screen presentations with all the trappings one is used to seeing in costly presentation tools. It also allows honest, real scientific presentations where one does not have to impress the audience with non subject specific stuff :-). The best thing about it is the possibility of saving the presentation as a html file. It makes portable network graphics files with each presentation slide. With a smattering of knowledge of html files one could put in a animated image as a image link thereby allowing one to show movies too when necessary.

Xfig : Though the man page claims that it is a facility for the interactive generation of figures ...., It in fact much more than that. Other than generating figures for elucidating what you want to say in a poster, it helps you import and export figures in a variety of formats, write text in various fonts and sizes, generate Greek symbols and color text, Save as latex picture file or any other format supported by your word processor for inclusion in your publications, generate GIFs of each page of the poster to put on your web site, and finally it generates *.fig files which are small in size. The only thing on my wish list for xfig is the capability to edit the imported pictures which are not in *.fig format. Therefore for a computer screen projected poster presentation you need a frames capable browser with contents in one frame and the xfig generated posters (exported as *.png or *.jpg from Xfig) on the other.