Setting up exchange for external email

Hi,
I need a little help setting up exchange for external email use. right now, exchange is setup for internal email only, and each user has a POP account for external email. Running Windows Small business 2003 Server. We are getting T1 setup at the office, and wanted to host our own email server. each user has 2 email accounts setup in outlook, POP, and Exchange. our exchange server is not “connected” to the POP server because of the 15min delay for inbound emails.

let me know if you need more detail.

thanks,
ed