Howtogeek posted a tutorial about customize fonts and colors for Gnome panel in Ubuntu Linux

Earlier this week we showed you how to make the Gnome Panels totally transparent, but you really need some customized fonts and colors to make the effect work better. Here's how to do it.
This article is the first part of a multi-part series on how to customize the Ubuntu desktop, written by How-To Geek reader and ubergeek, Omar Hafiz.

  How to Customize Fonts and Colors for Gnome Panels in Ubuntu Linux