buenos días
dmnt tendrías que hacer algo asi:
inicio.php
<?php require_once('Connections/conex_usuarios.php'); ?>
<?php
if (!function_exists("GetSQLValueString")) {
function GetSQLValueString($theValue, $theType, $theDefinedValue = "", $theNotDefinedValue = "")
{
if (PHP_VERSION < 6) {
$theValue = get_magic_quotes_gpc() ? stripslashes($theValue) : $theValue;
}
$theValue = function_exists("mysql_real_escape_string") ? mysql_real_escape_string($theValue) : mysql_escape_string($theValue);
switch ($theType) {
case "text":
$theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL";
break;
case "long":
case "int":
$theValue = ($theValue != "") ? intval($theValue) : "NULL";
break;
case "double":
$theValue = ($theValue != "") ? doubleval($theValue) : "NULL";
break;
case "date":
$theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL";
break;
case "defined":
$theValue = ($theValue != "") ? $theDefinedValue : $theNotDefinedValue;
break;
}
return $theValue;
}
}
?>
<?php
// *** Validate request to login to this site.
if (!isset($_SESSION)) {
session_start();
}
$loginFormAction = $_SERVER['PHP_SELF'];
if (isset($_GET['accesscheck'])) {
$_SESSION['PrevUrl'] = $_GET['accesscheck'];
}
if (isset($_POST['usuario'])) {
$loginUsername=$_POST['usuario'];
$password=$_POST['password'];
$MM_fldUserAuthorization = "";
$MM_redirectLoginSuccess = "index.php";
$MM_redirectLoginFailed = "inicio.php";
$MM_redirecttoReferrer = false;
mysql_select_db($database_conex_usuarios, $conex_usuarios);
$LoginRS__query=sprintf("SELECT usuario, password FROM usuario WHERE usuario=%s AND password=%s",
GetSQLValueString($loginUsername, "text"), GetSQLValueString($password, "text"));
$LoginRS = mysql_query($LoginRS__query, $conex_usuarios) or die(mysql_error());
$loginFoundUser = mysql_num_rows($LoginRS);
if ($loginFoundUser) {
$loginStrGroup = "";
if (PHP_VERSION >= 5.1) {session_regenerate_id(true);} else {session_regenerate_id();}
//declare two session variables and assign them
$_SESSION['MM_Username'] = $loginUsername;
$_SESSION['MM_UserGroup'] = $loginStrGroup;
if (isset($_SESSION['PrevUrl']) && false) {
$MM_redirectLoginSuccess = $_SESSION['PrevUrl'];
}
header("Location: " . $MM_redirectLoginSuccess );
}
else {
header("Location: ". $MM_redirectLoginFailed );
}
}
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Documento sin título</title>
</head>
<body>
<form id="form1" name="form1" method="POST" action="<?php echo $loginFormAction; ?>">
<table width="200" border="0" align="center">
<tr>
<td>Usuario</td>
<td><label for="usuario"></label>
<input type="text" name="usuario" id="usuario" /></td>
</tr>
<tr>
<td>Contraseña</td>
<td><label for="password"></label>
<input type="text" name="password" id="password" /></td>
</tr>
<tr>
<td colspan="2" align="center"><input type="submit" name="button" id="button" value="Ingresar" /></td>
</tr>
</table>
</form>
</body>
</html>
index.php
<?php require_once('Connections/conex_usuarios.php'); ?>
<?php
//initialize the session
if (!isset($_SESSION)) {
session_start();
}
// ** Logout the current user. **
$logoutAction = $_SERVER['PHP_SELF']."?doLogout=true";
if ((isset($_SERVER['QUERY_STRING'])) && ($_SERVER['QUERY_STRING'] != "")){
$logoutAction .="&". htmlentities($_SERVER['QUERY_STRING']);
}
if ((isset($_GET['doLogout'])) &&($_GET['doLogout']=="true")){
//to fully log out a visitor we need to clear the session varialbles
$_SESSION['MM_Username'] = NULL;
$_SESSION['MM_UserGroup'] = NULL;
$_SESSION['PrevUrl'] = NULL;
unset($_SESSION['MM_Username']);
unset($_SESSION['MM_UserGroup']);
unset($_SESSION['PrevUrl']);
$logoutGoTo = "inicio.php";
if ($logoutGoTo) {
header("Location: $logoutGoTo");
exit;
}
}
?>
<?php
if (!function_exists("GetSQLValueString")) {
function GetSQLValueString($theValue, $theType, $theDefinedValue = "", $theNotDefinedValue = "")
{
if (PHP_VERSION < 6) {
$theValue = get_magic_quotes_gpc() ? stripslashes($theValue) : $theValue;
}
$theValue = function_exists("mysql_real_escape_string") ? mysql_real_escape_string($theValue) : mysql_escape_string($theValue);
switch ($theType) {
case "text":
$theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL";
break;
case "long":
case "int":
$theValue = ($theValue != "") ? intval($theValue) : "NULL";
break;
case "double":
$theValue = ($theValue != "") ? doubleval($theValue) : "NULL";
break;
case "date":
$theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL";
break;
case "defined":
$theValue = ($theValue != "") ? $theDefinedValue : $theNotDefinedValue;
break;
}
return $theValue;
}
}
mysql_select_db($database_conex_usuarios, $conex_usuarios);
$query_usuario = "SELECT * FROM usuario";
$usuario = mysql_query($query_usuario, $conex_usuarios) or die(mysql_error());
$row_usuario = mysql_fetch_assoc($usuario);
$totalRows_usuario = mysql_num_rows($usuario);
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Documento sin título</title>
</head>
<body>
<form id="form1" name="form1" method="post" action="">
<table width="345" border="0" align="right">
<tr>
<td width="122">Usurio Conectado:</td>
<td width="105"><?php echo $row_usuario['usuario']; ?></td>
<td width="104"><a href="<?php echo $logoutAction ?>">Desconectar</a></td>
</tr>
</table>
</form>
<p> </p>
<h2>Bienvenido al index
</h2>
</body>
</html>
<?php
mysql_free_result($usuario);
?>
la conexión.
conex_usuarios.php
<?php
# FileName="Connection_php_mysql.htm"
# Type="MYSQL"
# HTTP="true"
$hostname_conex_usuarios = "localhost";
$database_conex_usuarios = "usuarios";
$username_conex_usuarios = "root";
$password_conex_usuarios = "";
$conex_usuarios = mysql_pconnect($hostname_conex_usuarios, $username_conex_usuarios, $password_conex_usuarios) or trigger_error(mysql_error(),E_USER_ERROR);
?>
saludos
Usuario y contraseña 
