My opinion.
Based on the reports which some folks like sbctsublc's put together, INS processes some 1.3k 485's every week. This includes approvals/transfers etc.. My 485 was filed in Dec 2002. There are around 37K 485's remaining from Jan 2002 to Dec 2002(again borrowing from the reports). So approximately it will take about 28.5 weeks or 7 months for INS to reach my 485 if they proceed as per FIFO logic. Since none of us know for sure the inner workings and logic behind INS operations, who knows how long it will take?
I should also add that a co-worker of mine who filed his 485 in Sep 2002 got his approval last friday.