sanrishi & others,
*Address change (prior to approval of GC) should be done both at VSC (or other applicable center) and at the state department.
VSC (or other center): You can send them a letter or call them to change the address (calling is easier)
State Department: Have to file AR-11!!! Someone's reply in this thread sounded like AR-11 was for records. In fact, AR-11 is the most important of all!!!!! The service center can/should be notified separately.
*Post approval, it suffices to file just the AR-11 with the state department.
Please note that notifying one (state dept. or service center) doesn't automatically take care of the other!
-Palaniappan Rajaram