How to Import an ICS to an iPhone
Instructions

Press the iPhone’s "Home" button below the device’s multi-touch display.

1. Tap the "Mail" icon on the home screen.
2. Tap the name of an email account to view its messages.
3. Tap the email message that has the attached ICS calendar file.
4. Tap the ICS file name in the email message window. A list of events appears.
5. Tap "Add All", and then tap the calendar to which you want to add the ICS calendar file events, and then tap "Done".