If you want to add an array's data to $SESSION while maintaining any other pre-existing session data:
foreach($array as $key => $value)
{
$_SESSION[$key] = $value;
}
If there is no other data in $SESSION that you need to keep, then you can just do:
$_SESSION = $array;
Or, you can use the second technique, but assign it to a sub-array of $SESSION so that you do not "disturb" other data:
$_SESSION['post'] = $_POST;
You could then access an given post element as $_SESSION['post']['name'].