array_diff:

$array = array('a','b','c');
$array_to_remove = array('a');

$final_array = array_diff($array,$array_to_remove);
// array('b','c');

edit: for more info: http://www.php.net/array_diff

edit 2: if you need to preserve keys, this really won't work, but neither will any of the other solutions presented thus far

array_diff:

$array = array('a','b','c');
$array_to_remove = array('a');

$final_array = array_diff($array,$array_to_remove);
// array('b','c');

edit: for more info: http://www.php.net/array_diff

array_diff:

$array = array('a','b','c');
$array_to_remove = array('a');

$final_array = array_diff($array,$array_to_remove);
// array('b','c');

edit: for more info: http://www.php.net/array_diff

array_diff:

$array = array('a','b','c');
$array_to_remove = array('a');

$final_array = array_diff($array,$array_to_remove);
// array('b','c');

edit: for more info: http://www.php.net/array_diff

edit 2: if you need to preserve keys, this really won't work, but neither will any of the other solutions presented thus far