From a quick search:
Works of art - sculptures, paintings, and even toys - are protectable by copyright. Furthermore, buildings created on or after December 1, 1990 are protected by copyright. A copyright owner has the exclusive right to reproduce a copyrighted work, and photographing a copyrighted work is considered a way of reproducing it. Thus, you may need permission to photograph a building or an art work.
Taken from
http://www.photosecrets.com/tips.law.html which has a ton of other info.
granted, random website, be warned... it may be inaccurate, but certainly represents what I understand to be true.