To get an interim EAD, go down to the local BCIS field office and take the following items:
1. A copy of your I485 RN
2. A copy of your I765 application receipt notice
3. Passport with I94
4. Letter from your employer or current pay stubs (not required but I was told to bring it with me just in case which I did)
The local BCIS issues interim EADs typically valid for 90 days.
rgds,
sadiq