Pango is an OpenSource framework for the layout and rendering of internationalized text. While it is an offshoot of the GTK2 and GNOME project, and the initial focus is operation in those environments, however there is nothing fundamentally GTK- or GNOME-specific about it.
Pango uses Unicode for all of its encoding, and will eventually support output in all the world's major languages.
One page links to Pango: