Google Calendar Map (GCM) puts all events with a location from a google calendar on to a google map.

First, make your calendar public:

1. In the Google Calendar interface, locate the “My Calendar” box on the left.
2. Click the arrow next to the calendar you need.
3. A menu will appear. Click “Share this calendar.”
4. Check “Make this calendar public.”
5. Make sure “Share only my free/busy information” is unchecked.
6. Click “Save.”

1. In the Google Calendar interface, locate the “My Calendar” box on the left
2. Click the arrow next to the calendar you need.
3. A menu will appear. Click “Calendar settings.”
4. In the “Calendar Address” section of the screen, click the XML badge.
5. Your feed’s URL will appear.