Hi
Except from the classic copy/paste u can use 2 other ways to have different objects share a material:
a)Groups:select the objects u want to share a material and create a group,then select the group and add a material.
Even if each of the objects have already a material then the group's material overrides it.
The advantage is that if u remove any object from the group then it restores it's original material.Also since the objects share the group's material any change u make to this material is for all objects ,something which u can't do with the copy/paste command.
b)Hierarchy:if u make one object parent to other ones and then assign a material to the whole tree then this material is assigned to the childs also.
Note that none of the objects should have a material assigned before..Also if u select one of the childs and assign a material then this object will have it's own material..
Best regards
George