Call to undefined function: mysql_connect()

i'am running a redhat 9 server, with php-imap-4.2.2-17 and i rpm'd mysql client/server 3.23.58. My problem is that apache / php is not recognizing my mysql_connect. WHen i look in php info i see that it is built --with-mysql=shared,/usr'

i'm running mysql properly because the ps auxw | grep mysql command gives me the following output:
root 1951 0.0 0.0 4140 4 ? S 09:43 0:00 /bin/sh /usr/bin/safe_mysqld --datadir=/var/lib/mysql --pid-file=/var/lib/mysql/dyn-10-213.nur.local.pid
mysql 1969 0.0 0.0 10680 36 ? S 09:43 0:00 [mysqld]
mysql 1970 0.0 0.0 10680 36 ? S 09:43 0:00 [mysqld]
mysql 1971 0.0 0.0 10680 36 ? S 09:43 0:00 [mysqld]
root 3647 0.0 0.5 3880 684 pts/1 S 21:19 0:00 grep mysql

but when i'm trying to connect mysql wit a php script i'm getting :
Call to undefined function: mysql_connect().

in php.ini there is :
extension=mysql.so
please could anyone help me to solve this problem b'coz i'm a newbie ?

Did you put your database name inside it?

mysql_select_db ("mydatabase");

Here is a comprehensive step by step tutorial

http://www.siteinaweek.com/installphp5/howto.php