For those of you who use a dynamic DNS service (DynDNS, no-ip, etc.), I wrote a C# based updater client. The project contains a class library, console app and service. It is designed to be extended to other mechanisms for fetching the IP and reporting it to the DNS server. Right now it uses the checkip service of dynDNS and updates RegisterFly.com. Full VS2005 project and source code available
here.