[Upated 26 Aug. '07 - The team of participating Rabbis of the United Noahide Academies have researched this question in greater depth, and found that for Gentiles, a protruding image of the face of a person is not forbidden, unless it is specifically something that is being worshipped as an idol. A full 3D anatomically correct sculpture of a person - front, sides and back - is forbidden, unless it is nullified as described further down.]
Shalom,
The [3D] form of a human or of the celestial bodies, made of any material be it gold, silver, wood, plaster, stone, etc., are classed as idolatrous images. The three-dimensional image must be one that is full on all sides, but one that is engraved, painted or woven is not defined as an idol. Other three-dimensional forms such as animals, plants, dragons, etc. are all permissible to own, unless the object itself is worshipped as an idol.
Shalom,
The [3D] form of a human or of the celestial bodies, made of any material be it gold, silver, wood, plaster, stone, etc., are classed as idolatrous images. The three-dimensional image must be one that is full on all sides, but one that is engraved, painted or woven is not defined as an idol. Other three-dimensional forms such as animals, plants, dragons, etc. are all permissible to own, unless the object itself is worshipped as an idol.
Rabbi Yitz