make title of the modules center instead of left?

How do I make the title of the modules such as HTML boxes, featured photos, and everything else be aligned <center> instead of sitting in the far left? Some of my page are at 100% width and it would look better is the title of the module is in the center instead of all the way over to the left.

If you have Chrome you can inspect elements, with FF it is best to install Firebug.  Turn off CSS caching in your admin.  From there you can inspect to see which CSS sheet and class is controlling the element.