From Daily Kos
Don't expect to find this in the US news. According to German's major news channel Der Spiegel, when George W. Bush's face appeared on the big monitor that showed part of the funeral the crowd erupted in loud boos (text in German):
Further down in the comments, you find that the more accurate translation is "boos and whistles." Again in the comments, it's said "In Europe, sports fans don't express disfavor with boos, they do it by whistling."