Kile - an Integrated LaTeX Environment

Latest available stable version for KDE3: 2.0.3.
Latest available unstable version for KDE4: 2.1 beta 4.

What is Kile?

Kile is a user friendly TeX/LaTeX editor for the KDE desktop environment. KDE is available for many architectures such as PC, Mac, and BSD.

The main features are:

Compile, convert and view your document with one click.
Auto-completion of (La)TeX commands
Templates and wizards make starting a new document very little work.
Easy insertion of many standard tags and symbols and the option to define (an arbitrary number of) user defined tags.
Inverse and forward search: click in the DVI viewer and jump to the corresponding LaTeX line in the editor, or jump from the editor to the corresponding page in the viewer.
Finding chapter or sections is very easy, Kile constructs a list of all the chapter etc. in your document. You can use the list to jump to the corresponding section.
Collect documents that belong together into a project.
Easy insertion of citations and references when using projects.
Flexible and smart build system to compile your LaTeX documents.
QuickPreview, preview a selected part of your document.
Easy access to various help sources.
Advanced editing commands.

Check out the screenshots section for some visual impressions.

With some tweaks Kile can run natively on a Windows machine. However, Windows support for Kile is still in an experimental stage.