Software for RHEL is available via up2date. You are using a commercial distro, so you should expect to pay for support. If you want free support, you should use a free distro. Stands to reason.
In your case,
Conga has been released for RHEL5. So I would be very surprised if you could find rpms for RHEL4. If you have paid support, you will be able to update your distro.
(I note that Conga is supposed to be part of RHEL4.5 ... but I suspect it is only in the repo.)
http://sources.redhat.com/cluster/conga/index.html
... you could have a go installing from source. Or try a different distro - AFAIK: CentOS and fedora both have conga rpms.
