|Desktop iCalendar Help|
To add a new category, just follow steps below:
Find a new png file which size is 16*16, and rename it to the name of new category.
Right click the events window and select "New events..."
Click "New category..." button
Locate the png file and click "Open"
All the category icons are stored in %appdata%/desksware/desktopicalendar/CategoryPic. You can add, delete and rename them manually.
Famfamfam has a pretty, free icon set. You may pick up some icons there.