Changing colour of blue bar on pages.

I'd like to change the colour of this bar (just below Home, Log In, Account etc) to green. Does anyone know how I can do this?

Many thanks,

Download from catalog/view/theme/default/image the following images:

header_1_center.png
header_1_left.png
header_1_right.png
tab_2.png (assuming you also want to change the tab colors to match)

Change to whatever color you want using you favorite image editing software, and reupload.