They have remote users that do not log on to their server, but can collect emails by dialing into the pop account via the web. How can emails be received on the BlackBerry and on the user's laptop?

Our client has an SBS 2003 Exchange server with mailboxes set up.

You need a BlackBerry Enterprise Server to deliver mail to their BB. If your running OWA you can use BIS.

The user has BES 4.1 installed.