Windows 2000 server with microsoft exchange 2000

we were hosting our own mail on our exchange 2000. All computers are using outlook 2002 on a domain to configure their e-mails from exchange. Our company recently switched the e-mail from our domain exchange server to a pop 3 provider and our outgoing smtp is through dsl outgoing.verizon.net server. They would like to only have internet mail delievery. The problem is no one can send or receive messages after setting up the pop3 and smtp providers. I see that the original configuration still exsists in outlook and we are trying to have internet mail delivery only and not use the exchange services anymore. What can we do help?