You would set up your button to point to something like "MyProfile.php" and when the user is logged in and lands on that page the information that is presented to them can be specific to just that user with a simple query to the database using session variables to retrieve the info for that user. For example:
$sql=mysql_query("SELECT * FROM users WHERE id='$_SESSION[user_id]'");
echo ' Welcome '.$user.' ';
Of course you can have it look up whatever info you want.