$array = array(
1 => 'one',
2 => 'two',
3 => 'three',
4 => 'four',
5 => 'five',
6 => 'six',
7 => 'seven',
8 => 'eight',
9 => 'nine',
10 => 'ten'
);
foreach ($array as $key => $value)
{
if ($key % 2) {$odd[$key] = $value;}
else {$even[$key] = $value;}
}
print_r($odd);
print_r($even);