OWA -Single Server Senario

I have one exchange 2003 server

I would like to allow to users to log on from

home through the internet to access the email

accounts through OWA we have internet/public email thru a pop3 app connecting thru a xp pro

workstation with a public ip address

also a website that i wanted add a link for our

employees and forward them to our exchange. server? but i only have one exchange server. running smtp connector (forwarding public emails )