Currently Being ModeratedJan 23, 2013 6:43 AM (in response to DM6156)
I found one post on another site indicting they had same issue, however, the solution they used is not my issue.
From the other site:
"To get the iPhone to recognize that a meeting request has been responded to in Outlook so it stops asking you to accept/decline, do the following in Outlook (This should work for Outlook 2003 and 2007, not sure about other versions): Go to Tools->Options->Email Options->Advanced Email Options. Look for the item called "Delete meeting request form Inbox when responding" and make sure it is selected.
If it was already selected then you have a different issue then I did. This has solved my problem 100%."
I already had the option selected, it was set up before I even had an iPhone.