Show module positions of any Joomla! website?
Add the parameter ?tp=1 behind the URL, e.g. http://www.joomla.org/?tp=1
The following parameters can be used: 0=normal, 1=horiz, -1=no wrapper.
Technical background: In Joomla 1.0.15 this functionality is called "function mosLoadModules" and can be found in /includes/frontend.php (Joomla 1.0.15: line 122).