If you use google apps and an iPhone or iPad you have probably tried to add other calendars to your in app calendar application. A very simple way to do this is to use iphoneselect. Iphone select allows you to select the calendars from a webpage and then configure your iPad or iPhone app to sync with them
You will then see your available calendars to sync with, the same selection you have in the gmail web application. This great little url can quickly configure your calendar.
I recently configured my cousins google apps account and allowed him to sync the other team members.