Get yourself firefox and firebug add on, use this to inspect the element your want to change.
Doing this you’ll find that the module headers are determined by h3 in the style.css in the folders:
styleselements…..what ever colour selected as default element colour.
To create a new element colour set, duplicate one element folder – rename it to what colour you’re going to use as base colour – then edit styles in this foder as required. Note once uploaded this new folder name will show up in the 1.5 template parameters, for 1.0.x you’ll need to set it in the ja-vars.php parameters.
i.e in lines
$theme_elements = “black”; // blank for default; “-1” for none select; otherwise, you can choose “black”,”blue”,”green”,”red”;