TeXnicCenter

The OP has requested one of the many editors available for LaTex, there may be another one that is already portable, or easier to make portable.

Here is the info on LaTex you requested:

LaTeX is a document markup language and document preparation system for the TeX typesetting program.

It is widely used by mathematicians, scientists, philosophers, engineers, and scholars in academia and the commercial world, and by others as a primary or intermediate format (e.g. translating DocBook and other XML-based formats to PDF) because of the quality of typesetting achievable by TeX. It offers programmable desktop publishing features and extensive facilities for automating most aspects of typesetting and desktop publishing, including numbering and cross-referencing, tables and figures, page layout and bibliographies.

LaTeX is typically distributed along with plain TeX. It is distributed under a free software license, the LaTeX Project Public License (LPPL). The LPPL is not compatible with the GNU General Public License, as it requires that modified files also modify the actual physical file names; this was done to ensure that files that depend on other files will produce the expected behavior and avoid dependency hell. A new version of the LPPL that will be compatible with the GPL is under development. The LPPL is DFSG compliant as of version 1.3. As free/open source software, LaTeX is available on most operating systems including Linux, Unix, Windows, and Mac OS X.