Creating wire frame diagrams and quick screen mock-ups shouldn’t be a difficult job, but finding the right software to make the job easy actually seems difficult… until now.  If you own Microsoft Visio, it’s worth reading How to use Visio for rapid prototyping on Guuui.com. In the article, you’ll find downloadable Visio templates called the "GUUUI Web Prototyping Tool" that make creating web site wire-frame diagrams a snap.  In addition to the templates, there are many great tips in the article that should make your life quite a bit easier.