Latexdiff
Using Latexdiff For Marking Changes To Tex Documents
05 08 13 • 22:29& Filed in: Latex
Latexdiff is a Perl script, which compares two latex files and marks up the significant differences between them. Various options are available for visual markup using standard latex packages such as "color.sty".
Project webpage: http://latexdiff.berlios.de/
CTAN page: http://www.ctan.org/tex-archive/support/latexdiff
An example output