DoLaTeX - - Latex editor with syntax highlight, document structure tree view and project handling. Latex output allows direct jump to warnings/errors, Projects folders gives support for figures/graphs. (Python, Pre-Alpha.
Euphoria - - An editor taiored for LaTeX editing. List of features and SourceForge project page.
LaTeX - - Michael Prokop describes the usage of VIM as an editor for TeX.
Tcltexed - - A simple text editor based on the script language Tcl/Tk, especially adapted to LaTeX written by Martin Strauß. Contains short description, downloads and screen shots.
Texmaker - - Open source multiplatform LaTeX development environment written using Qt. Features overview and download.
Vim-LaTeX - - Environment for editing LaTeX in Vim. Huge set of menus and shortcuts, improved syntax, compiler and ftplugin files, and recognition of \usepackage commands.
Winefish - - Open source LaTeX Editor written using GTK+ and based on Bluefish. Berlios project page, screenshots, forum and mailing lists.