SharePoint Calendar Plus web part allows users to view schedule data collected from various sources, such as:
Exchange Server private/shared calendars
SharePoint lists on various or multiple WSS sites
Custom calendar providers (CalendarPlus professional only)
It allows a user to receive a single, aggregated view of all events and meetings (both private and shared).
SharePoint Calendar Plus also works with SharePoint 2003 and MOSS 2007, product upgrade is included in standard support.
SharePoint Calendar Plus web part displays each event in a color that indicates its source.