If you ever need to prototype an application that your are creating for the PC/Mac, the web or mobile devices, there is a free tool available from Infragistics.
Indigo Studio lets you quickly create functional, animated UI prototypes.
Whether you're a designer without developer skills, a developer without design resources, or anyone with a great idea - you can design storyboards in real-world context, quickly prototype application design interactions that integrate with your storyboards, annotate those designs, and share your best designs with team members and key stakeholders. What's more, you don't need to spend a fortune on incomplete prototyping and static wireframing tools. Indigo Studio does things better – delivering rich, interactive experiences. And for a whole lot less – like Free!