When you color code a shared calendar by user, you can tell by just looking at the calendar if someone is busy. You need Outlook 2002/2003 to use this tip and have no more than 10 people using the calendar, since Outlook only supports 10 colors. (Color-coding in Outlook 2000 is available only in table view.)
Assign each user a Label color and if they forget to use their label color, you can create a custom view to apply the colors. Create a custom view by selecting the View, [OL2003: Arrange By], Current View, Define Views, New Day/Week/Month view) for the calendar and use Automatic Formatting to color-code the items based on the Organizer field.
Published January 5, 2004. Last updated on May 16, 2011.