The UI is one of the most important part of an application. Jeff Atwood wrote in a great blogpost, that the UI should be the first thing you do.
Unfortuantly there are many methods how to prototyp a UI. I found a very interesting video in the blogpost from Jeff: UI Prototyping with PowerPoint 2007.
PowerPoint? Ich don´t want a presenation!
Why PowerPoint? PowerPoint 2007 has some great features which allows us to build such an UI in very short time:
(I currently work on this project)
A important note: This is only the prototyp!
You can see some of the components and the general design and it looks better than with Paint or on a paper. The advantage of PowerPoint: It is still simpler to use as Photoshop!
Everyone (Projectleader, Designer, Developer) who can work with PowerPoint has the chance to bring his ideas into the design! It´s simpler to edit instead of a Photoshop image or a HTML dummy.
Features of PowerPoint 2007:
There are many effects:
You can use the templates:
And the "cool" effects:
(sorry - I have only the german version of PowerPoint)
With these tools you are able to build very fast a good-looking UI prototyp.
Another interesting site with the "UI Prototyping" Topic.
If you look for alternativs read Jeffs Blogpost :)