2次元配列の2次元目の配列の値でソートをする ref: http://qiita.com/tadasuke/items/e7be0d214e02105ab6d8

file0.php

$array = array(
    array(
        'id' => 10,
        'name' => 'hoge',
    ),
    array(
        'id' => 3,
        'name' => 'fuga',
    ),
    array(
        'id' => 20,
        'name' => 'foo',
    ),
    array(
        'id' => 1,
        'name' => 'bar',
    ),
);

file1.php

function sortArrayByKey( &$array, $sortKey, $sortType = SORT_ASC ) {

    $tmpArray = array();
    foreach ( $array as $key => $row ) {
        $tmpArray[$key] = $row[$sortKey];
    }
    array_multisort( $tmpArray, $sortType, $array );
    unset( $tmpArray );
}

file2.php

$array = array(
    array(
        'id' => 10,
        'name' => 'hoge',
    ),
    array(
        'id' => 3,
        'name' => 'fuga',
    ),
    array(
        'id' => 20,
        'name' => 'foo',
    ),
    array(
        'id' => 1,
        'name' => 'bar',
    ),
);

// そのまま出力
print_r( $array );

// ソート実行
sortArrayByKey( $array, 'id' );

// もう一度出力
print_r( $array );

file3.txt

Array
(
    [0] => Array
        (
            [id] => 10
            [name] => hoge
        )

    [1] => Array
        (
            [id] => 3
            [name] => fuga
        )

    [2] => Array
        (
            [id] => 20
            [name] => foo
        )

    [3] => Array
        (
            [id] => 1
            [name] => bar
        )

)
Array
(
    [0] => Array
        (
            [id] => 1
            [name] => bar
        )

    [1] => Array
        (
            [id] => 3
            [name] => fuga
        )

    [2] => Array
        (
            [id] => 10
            [name] => hoge
        )

    [3] => Array
        (
            [id] => 20
            [name] => foo
        )

)