Word wrapping SharePoint 2010 list column headers using CSS

 Add  a Content Editor Web Part (CEWP)

    1.Go to your list. Select Site Actions < Edit Page
    2.Click “Add a web part”
    3.Select Content editor webpart and click add new content.
    4.select html--< Edit Html source and add following css:

<style type="text/css"<
.ms-vh, .ms-vh2-nograd, .ms-vh2, .ms-vb
{

white-space: normal;
text-align:center;
vertical-align:text-bottom;

}
</style<