From wwww.my.domain.com to my.domain.com

[Alessandro Coppelli <coppelli dsea unipi it>]

  Hi to all.

  Sorry for simple question :


   I want to change the main URL  www.my.domain.com  in my.domain.com


 ex: I want that a clinet on your browser use http://my.domain.com
instead

  of www.my.domain.com.

 What I must do to in my configuration on the my site  ?


 Alessandro