There are six screws to remove (if you have an iBook without Firewire the screw circled in orange will not be present):

Two short, flat-headed Phillips screws near the battery compartment.

One short, round-headed Phillips near the speaker cable connector. (This is present on some models, but not others - especially the older ones)

One short, flat-headed Phillips between the ethernet and USB ports.

One short, flat-headed Phillips to the left of the hole-y (polite laughter) area.

One long, round-headed Phillips screw near the power receptacle.