Through Google Apps is it possible to have multiple personnel calendars which can be shared with various people?
What do I need if so? Do I need a particular subscription with Google or is this part of the free Google Calendar feature set?
With your free Google account you can share a particular calendar. You can check all the settings on the documentation here.
To create a new calendar, just follow these steps:
You can share this calendar with other people, by sharing the calendar's address. To find a calendar's address:
In the calendar list on the left side of the page, click the down-arrow next to the appropriate calendar and select Calendar settings (Alternatively, click the 'Settings' link at the bottom of the calendar list, then click the appropriate calendar.)
Click the ICAL button in the Private Address section at the bottom of the page, and copy the displayed URL.
Once you have this address, you can email it out to anyone with whom you would like to share the calendar.