Windows – How to find out what the external IP address is


My computers are sitting behind a router/firewall. How do I programmatically find out what my external IP address is. I can use for ad-hoc queries, but the TOS don't allow for automated checks.

Any ideas?

Best Solution appears to be a workable alternative, as now requires membership for their automated link. They very kindly appear to be offering this service for free, so please don't abuse it.