Problems installing RPMS

Hello:

where can I find libpq.so.1?

I am trying to install DBI/DBD for postgreSQL. I found
perl-DBI-1.06-1.i386.rpm on rpmfind.net and it installed just fine but
when I tried to install perl-DBD-Pg-0.91-1.i386.rpm I get a message that

this package needs libpq.so.1. What package do I need to install to
find libpq.so.1? Is there a later version of perl-DBD in RPMS format
out there?
I am really adverse to putting anything on my system that is not in rpm
format.

I have the following currently installed:

postgresql-clients-6.4.2-8mdk
postgresql-devel-6.4.2-8mdk
postgresql-data-6.4.2-4
postgresql-6.4.2-8mdk
perl-DBI-1.06-1
perl-5.00503-3mdk

I want to install:
perl-DBD-Pg-0.91-1.i386.rpm

thanks

astromonk
(please CC: me on email if you post to the mailing list)