Two types of fitting, Bayonet and Edison Screw.
Usual type is Bayonet, to remove, push the lamp in slightly and turn anticlockwise, as you look at it. fitting is the reverse.
E.S. fitting unscrew anti clockwise.
Careful if you have smashed the glass bulb. remaining parts, could be live.Turn power off. Also careful of the glass remains, use a thick cloth
Sheepdog, November 2008