Use Ubuntu 9.10 Karmic Koala Icon Theme In Older Versions

You can install the Karmic icon set, called 'Humanity', in the older versions of Ubuntu by opening a terminal and typing (without quotes): 
"sudo apt-get install humanity-icon-theme"





The entire icon set weighs in at 1.4MB and each icon is saved in SVG format which means the icons should look good in a variety of resolutions.