I’ve been in search of a great prototyping tool for a long time and finally have come across one; Balsamiq. It allows a team to quickly produce application mock ups to represent UX and UI concepts. The part I really like is that it visually represents the application as if you drew it by hand with a pencil; this has the psychological effect of forcing you to look at what the UI represents rather than the look and feel. You should already be doing prototypes for your applications because developers are VERY expense. Take a look at it and let me know what you think.