Does the iPhone support or read iCalendar / Outlook Meeting Invitations / .ics files?
UPDATE: Apple will include .ics support in iOS 4.2. Release date is November 2010.
We get a lot of emails asking something along the lines of "why does my iPhone not read/recognize .ics files?" The question itself is the answer.
Despite the fact that the OS X Mail App handles ics files just fine (displaying the event/meeting details within the email window, and entering the meeting info into iCal when the attachment is clicked), the iPhone completely lacks this support.Instead, the iPhone simply shows the .ics file as an attachment that it refuses to open or do anything with.
It was reported that iPhone OS 3.0 would contain support for .ics files, but that's no longer the case.
Newest iPhone FAQs
For now, you'll need to live with opening the .ics attachments on your PC/Mac and syncing the meeting/event details over to your iPhone.