apaceh & google duplicate content

Hi, i wish to avoid google duplicate content issues with site so need to have redirect for

http://site.com
to
www.site.com

This can be done via htaccess, but is bit of a kludge, can also be done via Apache with:

Code:

<VirtualHost *>
  ServerName www.example.com
  Redirect 301 / http://example.com/
</VirtualHost>

In ispconfig where do i put this?

Does it need to be done for each domain or can i have general setting?

Also can it be added to a template for future domains?

thanks