If you are from a NSERS country, it may explain the delay. I've been waiting for my EAD since December 2002 -over 4 months. Try calling the IIO to at least see if your case is assigned to an officer. In my case I got an interi, EAD from the Portland, OR BCIS office the same day that I applied. For some reason they did not charge me any fees, but it was only valid for 90 days. I have to go back and get a new one if my I765 application is still not adjudicated. Call your local office before you go to find out their policies.
good luck,
sadiq