I have never figured out how to remove the housings. But to replace the bulbs, I put HIDs in mine and found the passengerside MUCH easier than the driver side. On the passengert side all you have to to is remove the air intake (simple flat head screw driver is all thats needed), then just remove the plastic pop stop holders and then you can move the black mesh blocking the back of the headlamp and just reach in and twist. Very simple. Reverse to put back together.
Driver side is harder, simply becuase I have huge hands. I was never able to get full access back there. I removed the second battery tray, and the washer fluid tank and got 85% access back there, enough to change the bulbs out.