trying to move from MySQL

Looking to move from MySQL to PostgreSQL but I just can't seem to get
PostgreSQL to run.

I'm using Red Hat 6.2 (with latest updates/patches)

I'm thinking the problem is when I install the
postgres-server-7.0.2.i386.rpm package I get an error message of:
/sbin/ldconfig warning: can't open var/tmp/rpm-tmp.20991 skipping

even though I get that message I can start the database inside of Linuxconf
and it says it's running.  But I can't connect to it.  I've exhausted the
readme files that came with the RPM and I'm still lost.

Can anyone make some suggestions?

Thanks
Jason Carlson