Open Source Text Editor

1. jEdit Programmers text editor
   jEdit is a mature and well-designed programmer's text editor with over 9 years of development behind it. To download, install, and set up jEdit as quickly and painlessly as possible, go to the Quick Start page.
   While jEdit beats many expensive development tools for features and ease of use, it is released as free software with full source code, provided under the terms of the GNU General Public License. 
   
2. FCKeditor - The text editor for Internet
   This HTML text editor brings to the web many of the powerful functionalities of desktop editors like MS Word. It's lightweight and doesn't require any kind of installation on the client computer.
   Because it is Open Source, you may use it however you want.
   Features 
   Internet Explorer 5.5+ and Gecko browser (Mozilla / Firefox / Netscape) compatibility 
   XHTML 1.0 support 
   
3. Free Programmer's Editors,ASCII Text Editors
   This is the freeware sibling of the commercial Notepad Standard. It has lots of features, and can handle multiple files up to 2GB in sizes, if your memory permits. One handy feature it has is the ability to display a tab for each document you have open under the toolbar, which makes it convenient if you are navigating around with a mouse. In spite of the fact that there is no source code syntax highlighting, it's one of my current favourites. (To get the free version from the above link, click the "NoteTab Editors" link on the side panel.)
   
4. Syn text editor Open source Text and Programming Editor
   Syn is an Open Source Text and Programming Editor with Syntaxhighlight for many Languages, and some IDE Features, like starting a program (e.g. Compiler) and capture the output, support for Projects etc. Syn is written in Delphi (Version 5, Updatepack 1) for maximum performance, stability and filesize ;-), hence it doesn't require any bulky VC++/VB Runtime or MFC libraries!
   
   Syn supports Active Scripting, this means you can extend the functionallity with writing a Script. If you have written such a Script, or an other file (Autocomplete file or whatever), and you think it could be useful for others, just send them to me or to the Users Mailinglist (syn-users[at]lists[dot]sourceforge[dot]net), and we will add them. Of course, we will give you proper credits. Many thanks to all of you!
   
5. XEmacs text editor
   XEmacs is a highly customizable open source text editor and application development system. It is protected under the GNU Public License and related to other versions of Emacs, in particular GNU Emacs. Its emphasis is on modern graphical user interface support and an open software development model, similar to Linux. XEmacs has an active development community numbering in the hundreds, and runs on Windows 95 and NT, Linux and nearly every other version of Unix in existence. Support for XEmacs has been supplied by Sun Microsystems, University of Illinois, Lucid, ETL/Electrotechnical Laboratory, Amdahl Corporation, BeOpen, and others, as well as the unpaid time of a great number of individual developers.
   
6. Best Open Source Text Editor
   Few programs arouse the advocacy that the simple texteditor can. Its the software that we run all the time, and it needs to fit us like a glove. Except when you take off the glove and slap the crap out of someone using an inferior text editor. This category really exists just because we like flamewars. The nominees are of course Vim, Emacs, XEmacs, Pico and Joe. Fight it out for the winner and Vote for the one the deserves it.
   
7. aynHTML
   aynHTML is an open source html editor for use with internet explorer 5.5+, written in dhtml/javascript. the editor is a free piece of software released under the terms of the gnu general public license.
   the editor is meant to be used as part of a website management application, allowing users to load, edit and save content to a webserver. though the editor can be used standalone, many of its features, such as image upload and creation of internal hyperlinks, necessitate the use of a webserver.
   :: features ::
   * load and save content through html or xml
   * import internal and linked stylesheets
   * image upload and file manager
   * internal and external hyperlinks and anchors
   * editor api allows to customize both behaviour and appearance
   * html code view with syntax coloring 
   
8. Bitflux Editor - The Wysiwyg XML Editor
   Bitflux Editor is a browser based Wysiwyg XML Editor – and that changes everything! You can edit now your content semantically and at the same time display it to your users and editors in its final form.
   
9. Open Source Rich Text Editor 
   Kupu is a rich-text ('WYSIWYG') editor for browsers, written entirely in JavaScript. It runs on Internet Explorer and Mozilla based browsers, and produces well-formed, clean (X)HTML. It can (optionally) save to a page without reloading, provides generic browser interfaces to the server (so-called 'library drawers') to browse for images and links and has a large set of tools (functions) available, as well as providing an API to easily roll your own.