GarbageIP

GarbageIP was created to view and copy your external IP. Use is pretty straightforward. Just double-click from Finder or click once from the dock to launch, and your IP will appear in your menu bar.

From there, you can, well, view it. You can also copy it, show GarbageIP's about window, quit GarbageIP, and uh, that's about it. Requirements
PPC, Mac OS X 10.2 or later