Controlling things by having the PC fetch mails is a very good alternative, and have the advantage that the PC will not need a public IP. Best is if the receiving software can handle encrypted or signed mails, to avoid the possibility that a spam mail gets incorrectly processed. In some environments, other people may also be able to read network traffic and may pick up any clear-text passwords in a mail.

If the PC has a public - but not static - IP, then another alternative is to let it use dyndns and register the current IP.
http://www.dyndns.com/

The disadvantage with dyndns is that with the server software running inside the PC, the user must be able to drill a corresponding hole through the firewall. This doesn't work in a corporate environment, which is one of the reasons why so many virus software are using outgoing connections to a http listener functioning as a "concentrator", taking advantage of the fact that the majority of all firewalls allows outgoing http connects.