Option1
Create new User Acoounts for each user and create passwords for them. When a
particular user logs in, they will have their own Outlook data.
Option2
If you'd prefer to have single login, then you can create several Outlook
Profiles, each creating its own .PST file. Password protect the .PST files.
You can create additional Profiles using the Mail applet found in Control
Panel - just be sure to "Prompt for a profile" is selected.
You cannot have to mail accounts open at the same time in Outlook as only
one instance of Outlook can run at any time.
Option3
Use Outlook Web Access if connected to Exchange Server OR HTTP webmail if
facility provided by your ISP/company.
WWJ