iPhone Circular Progress Indicator -

I am trying to create a circular progress indicator like Pajam will represent progress during the recording. There will be a limited amount of time and I want to give it feedback on the sound level like a shaham. Where can a clue begin?

Thanks

A UIView subclass (probably circular progress: UIView < / Em>) and manually attach it with quartz (path, circle, etc.) passing through the% of progress on the drawRect method.