Files in /etc/php.d/

About a year ago, I installed RH 9.0 and in the process installed/updated php 4.2.2. The directory, /etc/php.d/ contains many ini files instructing php to load modules including mysql.so and interbase.so. phpinfo() shows that they have been included. Not being a Linux guru - in fact, knowing just enough to keep it running as my http and ftp server - and having lost my notes, I cannot remember what I did to get this configuration. In loading RH 9 onto another computer, the /etc/php.d/ directory does not contain these files *and* phpinfo() does not show mysql or interbase. Can someone help me get my bearings? Do I need to get the latest php rpm and run configure using the "--with-xxx" flag for each of the modules I want included? Lost..... Todd