Kroman is ultimate Korean hangul romanization tool. It has a lot of implementations.
This is the Objective-C library.
Install it with CocoaPod.
[Kroman parse: @손목시계]; // => son-mog-si-gye
Bug reports and pull requests are welcome on Github at https://www.github.com/cheunghy/kroman-objc.
Kroman is available as open source under the terms of the MIT License.