Wirefy is style-agnostic so that clients won't get hung up on the look or colors but just the content, functionality and hierarchy of information.
Crank™ Storyboard™ Suite lets UI designers easily prototype the look and feel of a product then deploy the prototype directly to an embedded device.
Create quick iPhone app wireframes in Keynote. Sketchkit includes pre-drawn iOS interface elements that can be used to create wireframes for iPhone apps.
Create UI Mockups / Wireframes and Use Case drive Storyboards in PowerPoint. Also automatically generate your functional test cases
A silly-fast way to create fully interactive mobile app prototypes.
Axure RP gives you the wireframing, prototyping and specification tools needed to create UX prototypes