Exchange Server 2003, Outlook 2003 and A.D.

Hi,
I?m kind of new in Exchange 2003 and A.D. administration. I?ve seen in different companies that they have their network configured in such a way that when a user logs in to their computer for the first time, they already have their Oultook 2003 already configured with their e-mail address. I never had the opportunity to ask and now I need to do the same thing on my network but I don?t know how to and I can?t seem to find any information about it on the network.
I thought that it was done through A.D. But how? it?s not by roaming profiles is it? Or is it by using a logon script? Can anyone help me with this, please? Thanks