With well configured VPN service, computers at different locations appear as if they are placed on the same company LAN, 24 hours. You no longer need to attach files to a e-mail message, send it via the modem to another office, for colleagues at remote office to receive it via a modem and place the attachment on the harddisk. What you need to do is to open a shared folder, drag the file to that folder, and colleagues at remote office can instantly read the file from their desktop. For robust communication, a company e-mail server can be installed at the company LAN and connected to the Internet 24 hours to send/receive e-mail. Security is assured by router level access control that can selectively enable which computer can access what, e.g. computer A can browse the Internet only, computer B can only receive e-mail.

Don't think that the charge for above service is sky high. They could be only marginally higher than the cost of your current single-computer dialup Internet access.

Fax and Voice services via the VPN is also possible that huge cost savings can be realised, such as when the remote office is at overseas.