How to create my own module in Freeradius !!!

Hi Techies, I am a new bie to freeradius fraternity. So grasping lot of things from this mailing list ;) I want to write my own module (which have a .c file prints out "Hello World" to a file). Would any of you please tell me on how can i do this. What all configurations are required? I am using Freeradius-1.1.3 server version. Regards Vineet