It originated in The Simpsons' 7th Season, Episode 2F32 with a comment by Groundskeeper Willie when he was drafted to teach French during a teachers' strike. He said, "Bonjourrrrr! Ye cheese eatin' surrender monkeys!".
BTW it's not the only anti-French comment uttered on The Simpsons according to this discussion thread: http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&th=eef024d02ef5e149&rnum=6
Willie seems to me to be a "Black Watch" type of guy. Thanks for the info.