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)
   http://sourceforge.net/projects/dolatex

etex LaTeX plug-in for Eclipse  
   The plug supports syntax highlighting, dynamic document outlining, a dynamic autocompletion engine driven by a user-extensible XML database and comprehensive BibTeX reference management.
   http://etex.sourceforge.net/

LaHelper - A LaTeX Command Helper  
   The application provides a menu system.
   http://lahelper.sourceforge.net/

LaTeX Plugin For Eclipse  
   The Project plans to manage LaTeX documents with eclipse. (Java/in Planning, Sources available)
   http://sourceforge.net/projects/eclipse-latex/

LaTeX-Editor  
   The project plans to build a Eclipse Plugin for LaTeX (Java/Alpha)
   http://sourceforge.net/projects/latexeditor

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.
   http://tcltexed.sourceforge.net/

LaTeX  
   Michael Prokop describes the usage of VIM as an editor for TeX.
   http://www.michael-prokop.at/computer/latex_en.html

Texmaker  
   Open source multiplatform LaTeX development environment written using Qt. Features overview and download.
   http://www.xm1math.net/texmaker/

WatchMyTexSource  
   A package with some preconfigured TeX files and tips for using TeX (primarily on Linux) which enables automatic update of the compiled (La)TeX document. It is not a self-contained editor, but uses standard tools on Linux.
   http://omnibus.uni-freiburg.de/~stierm/TeX/