This is a blue theme based on the Tango color scheme from FreeDesktop.org. The theme is released under the BSD license. There are two Tango Blue themes:
TangoBlue which uses black fonts
TangoBlueLight which uses light blue fonts and matches the wallpaper.

The wallpaper was created by/at: digitalblasphemy.com and it's under their licensing terms. The wallpaper can be found here:

http://www.digitalblasphemy.com/fshow.shtml?i=fluorescence6&w=1152&h=864&y=2000&n=Fluorescence%20&b=count&z=228358585275238832&m=144875699586354698&zs=fluorescence