How do I show the location of an event on a map?

In the Party section of your editor, click Edit for the event whose location you want to show. In a separate window or tab, open up http://maps.google.com

Enter the address you want to show and it should show up with a Pin in it. Then just copy and paste the URL you see at the top of the browser into the second space under Details for that event (back in your editor).