Via Google Blogoscoped, the Search Engine Watch suggests that googlecalendar.com is “currently registered to Data Docket, an Idaho company that often “holds” domains in their name to new Google services until the service or search tool is just about ready for launch.”
The article mentions how this was done with Google Earth. http://calendar.google.com also seems to be working but currently shows the Google Homepage. Both GCalendar.com and GoogleCalendar.com give me some kind of Site Administrator/User Administrator page.
This suggests Google may be getting ready to launch a calendar application. With GMail, it makes sense also to launch some personal information manager and organization applications. This is probably one of the things applications like Outlook do, but GMail doesn’t.