I can only find a partial answer to this question... where is this phrase from? (Where are the monkeys from?) And what does it mean? Are the monkeys seen as a positive/good or negative/bad 'omen'?
Click http://www.oldcopper.org/three_wise_monkeys.htm
and scroll about a third of the way down the page to the paragraph that opens: "Three wise monkeys are a favourite..." Most of what you want to know is probably there.