function quitaAcentos($string,$lowercase=true) {
	$string = preg_replace('`&(\w)[^;]+;`','$1',htmlentities($string));
	$string = $lowercase ? strtolower($string) : $string;
	return $string;
}
// echo quitaAcentos("copón") will show "copon"

It is a simple function that remove accents and puts its closest equivalent throught htmlentities and preg_replace, very useful for SEF url and aliases

Clear accents easy and fast

PHP