Ivan --
To delete an enterprise calendar in Project Server 2003, do the following:
1. Open Microsoft Project and log into Project Server with administrator
permissions
2. Click Tools - Enterprise Options - Open Enterprise Global
3. Click Tools - Organizer
4. Select the Calendars tab
5. Select the desired enterprise calendar from the list of calendars in the
right side of the dialog box
6. Click the Delete button
7. Save and close the Enterprise Global file
8. Close Microsoft Project
Hope this helps.