There is a great technique (not a tool but rather an aproach) called Canonical Abstract Prototyping.  When you need to design user interface this is a method to quickly get nice results. You just have to think what information shall be present on what screens. Visio is great for drawing this type of Prototype.

For more check Larry Constantines web page: http://www.foruse.com/publications/index.htm

Here are some examples I did: http://requirementsexample.weebly.com/user-interface-prototype.html