// Check for friends 
					$frnd="SELECT * FROM friends WHERE my_id='$_SESSION[user_id]'";
					$fres = mysql_query($frnd);
					$fnum = mysql_num_rows($fres);
					 while($fr=mysql_fetch_array($fres)){
						  $friend = $fr['friend_name'];
						  $friend_id = $fr['friend_id']; }

                                // Lookup address book 
				$addy="SELECT * FROM address_book WHERE my_id='$myid'";
				$abresult=mysql_query($addy);
				$adnum=mysql_num_rows($abresult);
                                  while($ab=mysql_fetch_array($abresult)){
							  $usr=$ab['email'];
							  $their_id=stripslashes($ab['their_id']);
							  $user_name=stripslashes($ab['nick']);
							  $their_username=stripslashes($ab['their_username']); }

SELECT * FROM friends
WHERE their_id NOT IN (
	SELECT their_id FROM address_book
)

SELECT * FROM address_book WHERE my_id = $myid

$sql = "SELECT * FROM address_book WHERE their_id != '$friend_id'"

$sql = "SELECT ab.*, f.* FROM address_book AS u INNER JOIN friends AS f ON ab.my_id = f.my_id WHERE ab.their_id !='$friend_id'";

SELECT * FROM friends AS f
WHERE their_id NOT IN (
	SELECT their_id FROM address_book
)

$sql = "SELECT * FROM friends WHERE my_id=$myid AND their_id NOT IN (SELECT their_id FROM address_book WHERE my_id=$myid)";

$sql = "SELECT * FROM friends WHERE my_id=$myid AND friend_id NOT IN (SELECT their_id FROM address_book WHERE my_id=$myid)";