The Javascript map viewer sample just got released.
Download it from the code gallery
What to see it in action? You can see it here http://geotwitter.net/demo/index.html
Description from the code gallery
This sample viewer was designed to showcase some of the core capabilities of the ArcGIS Platform through a simple, modern, Web2.0 style user interface. This sample may be used with simple modifications to its configuration files or its source code can be used by application developers to further explore and understand some of the best practices and programming patterns of the ArcGIS JavaScript API.
Download it and have fun
Cheers
Al