During our work over the last 15years we developed quite a few tools to make our lives as designers easier.
One of those is Discuss-App. This is a Web Application for communicating designs with others (e.g. clients) and creating screen definitions/style guides for the use by software engineers to implement designs into final software. Previously this was a tedious process, very error prone and hard to maintain.
Discuss-App is publicly available – give it a try: www.discuss-app.net