[CentOS] crypto, readline and zlib libraries - Postgres install

I have the 5.x Centos DVD and loaded it.

Please be gentle with me, as I'm nominally a FreeBSD kind of guy... :)

Anyway, I'm trying to install Postgres and the three libraries in the 
subject line are missing off the base installation.  I figured out how 
to load gcc using yum, but those libraries aren't there, and I need the 
former in particular in order to enable SSL for Postgres client 
connections.  A perusal of "yum list" with an appropriate grep or two 
doesn't elicit anything useful.

Anyone know where I find these?  I loaded just the standard distro, no 
graphical user environment (neither Gnome or KDB)

Thanks in advance.

-- 
Karl Denninger (karl at denninger.net)
http://www.denninger.net