AUCTeX is an extensible package for writing and formatting TeX files in GNU Emacs and XEmacs. It supports many different TEX macro packages, including AMS-TEX, LaTeX, Texinfo, ConTEXt, and docTeX (dtx files). AUCTeX includes preview-latex which makes LaTeX a tightly integrated component of your editing workflow by visualizing selected source chunks (such as single formulas or graphics) directly as images in the source buffer.
(add-to-list 'load-path "~/.emacs.d/auctex") (load "auctex.el" nil t t) (load "preview-latex.el" nil t t)
Emacs 24 and ELPA
If you install AUCTeX via ELPA in Emacs 24 the basic setup listed above is not necessary. AUCTeX just works out of the box (at least on Linux).
(setq TeX-PDF-mode t)
Configure view program
(setq TeX-view-program-selection '((output-dvi "DVI Viewer") (output-pdf "PDF Viewer") (output-html "HTML Viewer"))) ;; this example is good for OS X only (setq TeX-view-program-list '(("DVI Viewer" "open %o") ("PDF Viewer" "open %o") ("HTML Viewer" "open %o")))