We were just at MK this past Saturday (the 13th). We decided to hop to Epcot around lunch time because it was getting too crowded for our taste. Same thing Sunday at AK. We left at 1PM because the crowds were getting very thick.
We were chatting with a CM at AK. He told us this past weekend was the start of at least a month of heavy crowds.
Last year, tourism was down because of the Iraq situation, but it's definitely up again this year.
On the positive side, if you get there for opening, you have a couple of hours of tolerable crowds, and you can pack a lot in before it gets bad.