unfortunately the built in ICS subscription feed doesn't seem to work with iCAL (Apple Calendar) nor iOS devices (iPAD and iPhone).
There are a few workarounds:
Here is another Workaround:
You need to have a google calendar and setup sync with your Calendar and iOS devices.
You need to add the ICS feed to you google calendar.
after that, you should see your personal tech.ed schedule in your google calendar under "Other Calendars".
Next, (this is the key to getting the calendars on your iOS devices)
you must enable the new calendar feed to sync with your device.
and tick the new calendar "TechEd Australia 2012 Calendar (Read Only)"
Congrats!, you should now have some sync goodness on your iOS devices!