If you've completed your other projects, why not take the time to learn Objective-C? There is a ton of material out on the web to help you get started. Honestly, it won't be that hard and learning to do some memory management will be a great learning exercise. Have you programmed in C before?
Most cross compilers won't do a great job in converting your code, and debugging your project may become much more difficult if you develop them this way.
