phpinfo() doesn't show postgres as a configured module

When I run the PHP function phpinfo() on my server that has both Apache and PHP on it, it doesn't show postgres as a configured module.  I am running Apache version 2.0.54 and PHP version 5.2.8 (however the phpinfo() function displays that it is version 5.0.4 ; what is up with that???)

What command do I need to run to get the postgres module to work with PHP?  I have tried to configure the server this way and it didn't seem to fix it:

./configure --with-pgsql=/usr/local/pgsql/ --with-apxs2=/usr/local/apache2/bin/apxs
make

Any ideas what I am doing wrong?

-Mark