Application Fonts for debian

[Basanta Shrestha <basanta mpp org np>]

Dear List,
We are localizing gnome. I have added a font. There is no problem in 
changing this font for 'Application Font', 'Desktop Font' and 'Window 
Title font'. But I need to be able to make this  font the default font 
so that this font is used across whole gnome application interfaces. 
Please note that I can NOT use gui to do this!! Can any one tell me how 
to do this by directly modifying into files? This font should be default 
for all the login users that exists in the system.
o/s:  Debian linux

-basanta