Fonts using OpenGL - urgent

Hi All,
I am facing problems using different fonts in a Open GL program which i am developing in C on Linux platform.
I nedd to use different fonts for the application. How do i go about it. Is there a method of using True Type fonts in OpenGL programs. is so how do we import a true type font file. There are glf files which can be imported. but what about the true type font files. please help.
thanks in advance