ProjectBuilder was Apple's Integrated Development Environment (IDE) that shipped on the Developer Tools disk with Mac OS X pre-10.3. As of Mac OS X 10.3 Panther ProjectBuilder has been replaced with XCode, but is still available for download from the ADC software download page. ProjectBuilder is unsupported past 10.2 (but has been reported to run) just as XCode is unsupported on pre-10.3 systems.
It has all you need to write your application's code, with the interface being taken care of by InterfaceBuilder. Other things can be made with image, video, and audio editors.
ProjectBuilder topics: [Topic]