[fetchmail]How to set the boxes for user in IMAP server?

Hello!
I am a newbie for the mail server. I am using a RH 7.0
to build a IMAP server. I found the default box for
user is stored in /var/spool/mail. I want to know how
to set undefault box for user.

By the way, what kind of command should the user use
to login by fetchmail without using .fetchmailrc? 
fetchmail -u xxx -???

Thanks!

____________________________________________________________
Do You Yahoo!?
Get your free @yahoo.co.uk address at http://mail.yahoo.co.uk
or your free @yahoo.ie address at http://mail.yahoo.ie