continuous-rubber is a script that runs rubber (a latex/pdflatex wrapper; it is contained in most distributions, and reruns multiple times as neccessary) every time any of the input files are changed. A small systray icon is provided to force a recompile, open a PDF viewer. If any errors happend during compile, then the error is shown in a popup. It is also accessible via the tooltip hint.
Everything is available in a git repository. You can grab the most recent version using the following command.
git clone git://git.sipsolutions.net/continuous-rubber.git
You can also browse the code.
To install, install the continuous-rubber script into your path. Then you can also install the continuous-rubber.desktop file (or configure your file manager manually). This will enable you to "run" TeX files using continuous-rubber.
Simply start continuous-rubber with your TeX file as the first argument. Then edit any of the files, and watch as it recompiles your document when you save anything.