Invitation button in iPhone 3.0 beta 1 and 2.

Missing Invitation button in iPhone 3.0 beta 3.

I did not check if a new Invitation event that has not been accepted look like in beta 2 but this is what it looks like in beta 3:

There does not appear to be a way to accept a meeting invitation. The meeting invitation was created on Google Calendar.

On the invitees menu, the inviter has a green check mark next to the name while the invitee who has not accepted the meeting has a question mark next to the name.