$data = array(
"5|空|GoogleJP|",
"11|空|MSN|",
"1|雲|MSN|",
"4|雲|GoogleJP|",
"1|雲|goo|",
);
foreach ($data as $val) {
$array = explode("|", $val);
if (isset($hit[$array[1]])) {
$hit[$array[1]] += $array[0];
} else {
$hit[$array[1]] = $array[0];
}
}
arsort($hit);
foreach ($hit as $key => $value) {
echo $key . " " . $value . "<br />\n";
}

次からはPHPの質問スレへ行くように。