LaPsE - Project planning to manage LaTeX documents with Eclipse. - http://eclipse-latex.sourceforge.net/
eTeX - Plugin for LaTeX documents that supports syntax highlighting, dynamic document outlining, a dynamic autocompletion engine driven by a user-extensible XML database and comprehensive BibTeX reference management. (Also knows as ecleTeX.) - http://etex.sourceforge.net/
TeXlipse - Mature plugin which provides functionality for editing, building, and previewing (La)TeX documents. Site contains documentation, screenshots and downloads. - http://texlipse.sourceforge.net/