loguearme con PHP

[jmabreu]

<?php

include('../soft/function/conexion.php'); $link = Conectarse();

$user = $_POST['usuario']; $pass = $_POST['password'];

$consulta = "SELECT * FROM m_usuarios WHERE Usuario = '$user'";
$inf = mysql_query($consulta); $res = mysql_fetch_array($inf);

if($res['Usuario']==''){header ("Location: ../index.php?errorusuario=si");}else{
if($res['Usuario']==$user && $res['Password']==$pass){header ("Location: ../soft/index.php");}
else{header ("Location: ../index.php?errorusuario=si");}}

session_start();
$_SESSION["Usuario"] = $user;
$_SESSION["Nivel"] = $res['Nivel'];

?>