I’ve mentioned a number of tools to help with app localization such as the excellent Lin Xcode plugin.
Here’s another set of tools along with a library from Angel Garcia called AGi18n designed to help make it easier to localize strings within interface builder elements.
AGi18n automatically makes any strings within your interface builder elements without you needing to change any code within your apps.
There’s also a tool that makes it easy to inject your translated strings into the interface builder elements, and a library that uses some swizzling to make everything work.
Here’s a video from Angel demonstrating AGi18n:
You can find AGi18n on Github here.
Angel also has a nice writeup on his site comparing AGi18n with other string localization techniques.
A terrific project for helping with creating localized apps using interface builder.