Configuring Internet Mail
Click "Mail" or "Mail and Fax" in the control panel, add Internet mail by clicking "add" then clicking "Internet Mail". Once it is added, highlight and then click "properties". Fill in the Account info. Done. (A side note - not all machines have internet mail installed. If this is the case, install it in "Add Remove Programs" in the Control Panel.) Every time a different person logs in, they will have different email settings.
Configuring Internet Mail Multi-User Capabilities
To set-up multi-user capabilities click "Control Panel", click "Users", click "Add a User". Log off and then back in as the user you wish to be. This will set up a separate password file for each user. This also applies to dialup networking.