For setting to MS.exchange server 2003 to ISP

Hello All,
I am hoping someone can help with my problem. I have one network with clients 150. i have one active directory domain at windows 2003 base. i want to create one of exchange server 2003
on my network for our mail syatem. my problem is configuration setting for my exchange server to ISP.
i want to know it that is exchange server 2003 configuration setting to our loacl exchange server to our ISP.

best reguards,
Sai Wunna Aung
Network Admin
Myanmar.