The following two links seem to be exactly what you are looking for (many such positions in each one of them).
http://en.chessbase.com/post/can-we-still-deceive-computers-in-chess
http://www.chess.com/forum/view/general/positions-engines-get-wrong--please-contribute
A cute study, which engines are unable to solve last I checked (white to move and win):
6r1/p1p1p1pP/P1PpP1P1/8/2P1B3/2K3pp/3P2rq/R5bk w - - 1 0