In Outlook 2003 distribution lists are helpful for managing emails of the people you contact. Learn how to use the feature here.
In Outlook, you can create distribution lists that allow you to send an email to multiple people without having to type each person's email address or insert each address from your address book. This is especially useful if you typically send emails to the same group of people.
For example, let's say you have a group of eight friends who meet once a month for dinner. Rather than type each person's email address, you can create a distribution list and name it Friends. Now, all you need to do is insert your Friends distribution list into the To... field of my outgoing messages. This is much easier than typing each address individually.