DirectUpdate - DirectUpdate is a dynamic DNS updater with many features.
No-IP - Dynamic DNS and Managed DNS Provider
Dynamic DNS client for Windows - It’s essentially a PAR‘ed up version of a slightly modified ddclient, packaged as a Windows service...
iWantMyName - Register your own custom domain for web applications, email, blog or website such as Google Apps...
Dyn - Managed DNS, Outsourced DNS & Anycast DNS
DNS-O-Matic - DNS-O-Matic (dnsomatic.