Create your Overlays Map File
In MapServer the .map file is a workspace or project of layers that will be available to the user. This is the base that iShare then performs queries against via the MapSource (XML) file.
The best environment to work with MapServer MAP files is in Textpad as this allows for syntax highlighting.
Textpad can be downloaded from http://www.textpad.com/download/index.html
Configure iShare via iShare Studio
Please refer to the iShare Studio topic for details on how to configure iShare via the Studio.
Create your Tile Cache
Please refer to The Tilecache topic for details on how to build your tile cache.
Create your iShare Web Page
Please see the topic on Creating your MyCouncil page.