I have users who have:
1. Office e-mail account (Exchange)
2. Private e-mail account (SMTP/POP3).
3. Some other bussiness e-mail account.
I try to deal with this issue so that I configure both Outlook 2000/9x and Outlook Express on the same PC.
1. Use Outlook 2000/9x for Exchange accounts.
2. Use Outlook Express for SMTP/POP3 mail.
If your users need to use several Exchange accounts on several servers, configure multiple Exchange Profiles. Right click Outlook icon on desktop. Click Properties, click Show Profiles, Click Add. This will enable you to specify new Exchange or some other account.
If you are administrator and want to open several accounts on one Exchange server (like your own account, admin account, some services account etc), open Outlook, click File menu, click Open other user's folder etc.