SQL syntax error!

Ik heb dus dit:

<?
$sql = "SELECT * users WHERE username='" . $_POST['username'] . "' AND password='" . $_POST['password'] . "'";
$query = mysql_query($sql) or die("Error at logging in: " . mysql_error());
?>

Maar ik krijg de volgende error:

Error at logging in: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'users WHERE username='Admin' AND password='Admin'' at line 1

SQL = SELECT * users WHERE username='Admin' AND password='Admin'

Alvast bedankt!