Tiggr is an application that can be used for the creation of user interfaces. It has two distinct advantages, namely that it runs entirely on the browser, and that it can be used collectively. That is, you will be able to work with the other members of your team as if you were all in the same room. You will no longer have to email files back and forth. And you will be able to invite as many colleagues as you want, too.
Using Tiggr, interfaces are created by dragging and dropping controls into position, and all the many layouts that are provided will let you come up with the exact prototype that you can see in the eye of your mind.
It is important to mention that Tiggr can also be used for the devising of mobile interfaces. As it stands right now, Tiggr will let you come up with interactive prototypes for iPhones, iPads and Android phones and have them fully previewed, too.
GoTiggr.com In Their Own Words
Creating prototypes collaboratively.
Why GoTiggr.com It Might Be A Killer
It works entirely on the browser, and it can be used in conjunction with as many people as you want.
Some Questions About GoTiggr.com
How long does the creation of prototypes take on average? 
