dynis (=dynamic IP Stalker) is a package that can be first of all used to keep dyndns-entries up-to-date and second to resolve dyndns-entries to ip-adresses via a swt-gui.
Finally! An extensible, cross-platform dynamic, static, or custom DNS update client! This simple Java program will keep your domain name always pointed at your computer. Supports multiple ways for obtaining IP, updating domain, and reporting errors.