Well, I use «Xfce desktop environment» and (not like gnome or kde) doesn’t have an application to install/uninstall our themes and icons, so we should do it manually and for users who doesn’t know a lot of Linux might be a little hard.
I wrote an application to make this easier in Xfce, and works perfectly for me (tested in Xfce 4.4.0 and 4.4.1 with the distros Slackware and Ubuntu).

The files are here (with some screen shots).
http://icc.utalca.cl/~clizana/xfcetm/

You might view the README file first

Icons and themes can be downloaded from xfce-look.org

By the way this application sucks xD but make my life easier