The Perfect Setup - Debian Woody (3.0)... sending mail from my XP box?

[ExCIA]

BTW... this is one of the best HOWTOs website I've ever come across. Two thumbs up.

Anyway, I have completed the 'The Perfect Setup - Debian Woody' and what do I need to do in order to send mails from my XP machines (outlook) to my Debian server and let the Debian server deliver the mail to my ISP?

I have three XP machines in the network and the forth one is the Debian server (192.168.0.3). All is connected through a router (broadband).

My ISP's (NTLWorld) smtp/pop3 servers are:

smtp.ntlworld.com
pop.ntlworld.com

To send mail I have to use SMTP authentication.

For example, if my email address is john.doe@ntlworld.com does that means I have to create an account on the Debian server as john.doe?