NC Girl,
From what I understand now when you file an I-485 and also the work authorization, you will have an appointment to submit your biometrics at your local INS office. Biometrics include your fingerprint and signature. Before, this was done in person at an EAD appointment when the application was ready. Now, family based cases EAD are processed much the same way as employment based cases. Once you have submitted your biometrics, the application is fowarded to the national service center for processing and you will receive the card from them by mail. As long as your I-485 is pending, you will need an EAD. My husband's I-485 approval was pending for a total of 38 months; hence, the 4 EADs. He would renew his EAD about 90 days before expiration. Now, INS advises you renew 6 months ahead of expiration!!. If you do not get your EAD after 90 days after you have filed, you may apply for an interim EAD in person at your local INS office and it will be issued on the spot. An interim EAD is good for 280 days while the permanent one is good for 360 days date of expiration.
Hope this helps,
Kiska