Install the Lucid Light Themes (Radiance and Ambiance) in Ubuntu 9.10
Answer:
The new Lucid Light themes (Radiance and Ambiance) in Ubuntu 10.04 is very nice and it can also be used in older version of Ubuntu such as Ubuntu 9.10, so you don't need to upgrade if you only want the new themes.
What you need to do is the following (for Ubuntu 9.10).
1. Add the repository
# sudo add-apt-repository ppa:nilarimogard/webupd8
2. Install all the needed files
# sudo apt-get update && sudo apt-get install gtk2-engines-murrine ubuntu-mono light-themes gtk2-engines-aurora
3. Change it in action
Reference: http://www.webupd8.org/2010/03/ubuntu-lucid-light-themes-radiance-and.html