function myquery($sql, $args = array())
{
	$strpos = 0;
	$strlen = 0;
	while( !empty($args) && ($strpos = strpos($sql,'?',$strpos+$strlen)) !== false ){
		$str = mysql_real_escape_string(array_shift($args));
		$strlen = strlen($str) + 2; // 2 das ' antes e depois da str
		$sql = substr_replace($sql, "'" . $str . "'", $strpos,1);
	}

	return mysql_query($sql);
}

myquery("INSERT INTO mytable values (?, ?, ?)", array("field1", "field2", 3));