PowerMockup is described as 'PowerPoint add-in for sketching screens of web and desktop applications. The interface elements make it a breeze to prototype and evaluate different design ideas before proceeding to the implementation' and is a Wireframing tool in the development category. There are more than 10 alternatives to PowerMockup for a variety of platforms, including Windows, Web-based, Mac, Linux and SaaS apps. The best PowerMockup alternative is Pencil Project, which is both free and Open Source. Other great apps like PowerMockup are Balsamiq Wireframes, Wireflow, Axure RP and mydraft.cc.