User Accounts managemant

I am new to all this php script stuff. I was wanting to create a
website that would have phpauction but i was also wanting to run
several other php scripts like a calender and a directory and possibly
several other scripts. I was wondering if there is a way that a user
could set up one account and it would automatically create account in
all the scripts this would allow users to keep the same user account
for all services. Does that makes sense. I just want people to enter
their information once and then they would be would have accounts for
all the services thanks.

Try adding this line to all services:

<?
include_once('login.php');
?>


login.php:

<?
mysql_connect($db["host"], $db["user"], $db["pass"]) or die("MySQL
error");
mysql_select_db($db["admin"]) or die("MySQL error");
session_start();
if($action=="logout")
{
session_unregister('name');
session_unregister('passwd');
exit("You have been logged out.<br><a href=\"".$PHP_SELF."\">Log in as
another user.</a>");
}
if (!isset($name) && !isset($pass))
{
exit("<form name=\"login\" action=\"".$PHP_SELF."\"
method=\"post\">
<input name=\"name\" type=\"text\" value=\"\"><br>
<input name=\"passwd\" type=\"password\" value=\"\"><br>
<input type=\"submit\" value=\"Log in\">
</form>");
}
else
{
session_register('name');
$_SESSION['name'] = $name;
session_register('passwd');
$_SESSION['passwd'] = $passwd;
$query="SELECT pass FROM `users` WHERE
`username`='".$_SESSION['name']."' LIMIT 0, 30";
$row=mysql_fetch_array(mysql_query($query));
$pass=$row["pass"];
if($_SESSION['name']==$name and
md5($_SESSION['passwd'])==$pass)
{
echo "<p align=\"right\">User:
[".$name."]<br><a href=\"".$PHP_SELF."?action=logout\">Log
Out</a></p>";
}
else
{
session_unregister('name');
session_unregister('passwd');
exit("
<form name=\"login\" action=\"".$PHP_SELF."\"
method=\"post\">
<input name=\"name\" type=\"text\" value=\"\"><br>
<input name=\"passwd\" type=\"password\"
value=\"\"><br>
<input type=\"submit\" value=\"Log in\">
</form>");
}
}

?>