We\'re building a multi-user platform where each registered user has a Google App account with their e-mail and calendar.
People can add to the events to the calendar,
First log into your Google Apps domain admin account. The organization admin url is https://google.com/a/yourdomainname.com
Go to Apps > Calendar > Sharing Settings or here (substitute your domain): https://admin.google.com/yourdomainname.com/AdminHome?fral=1#AppDetails:service=Calendar
Choose Share all information, but outsiders cannot change calendars
Then log into the user account with the calendar.
The new setting took 5 minutes before it took affect on the user accounts. I logged out and back in a couple times, refreshed, etc. Eventually the Calendar share settings on the user accounts will allow you to change the default "See only free/busy (hide details)" choice to "See all event details" and you're done.