Ubuntu Mockup Tool. You can test both versions free for 30 days before deciding on a payment version. Mockplus is a rapid wireframing tool for designers to create interactive wireframes for websites and mobile apps which enables you to share and test design ideas across pcs and mobile devices from an early stage in the design process.
Mockplus is really a good choice for users at any level of experience because of the ease of use and the clean interface. 14 wireframesketcher is a rapid wireframing tool for eclipse based ides like aptana zend studio and the like. It s a cross platform application available in stand alone form or as a firefox add on.
It s very quick and web based so it will definitely work in ubuntu.
The balsamiq mockup or balsamiq studios is probably the best known web ui mockup tools for free on the list. You could probably use it for software application interface development as well. It also comes as a standalone version for all major platforms including ubuntu. Mockplus is a quick wireframe tool which is created by the fast growing startup jongde software llc.
