From what I see there seems to be a delay.  Even with the price of bitcoins dropping the miners are complaining that the difficulty is going way up right now.  The general understanding seems to be that with the latest buzz about bitcoin many people buy the equipment and start mining even when the difficulty of making bit coins goes way up and cost is prohibitive and little or no profit is possible.  So then you have to wait for those who are mining to give up and get out which takes awhile and then the difficulty will decrease.  Also some do mining just for the novelty of it and aren't that concerned about making a profit.  I was going to do mining just for that reason, just to see how it worked then I read this thread and thought maybe I should wait a while and pick up the stuff cheap on ebay.

http://forum.bitcoin.org/index.php?topic=20944.0