I have a newly installed red hat machine which I would like to install subversion 1.6 and httpd version 2.2.11 on. However, the newest version available in the rhel repository is 1.4.2 and 2.2.3 respectively. Is there another yum repository that I can connect to that will give me later versions of the software or am I going to have to build everything from source to get the latest versions?
One of the reasons you would select CentOS (or RHEL) is for a stable platform. One of the goals of a stable platform, is to not introduce major changes, which is the reason that subversion and apache haven't been updated on CentOS.
On the matter of 3rd party repositories, the only one that I trust binary RPMs from on my production machines is EPEL.
You will almost certainly need to update neon and sqlite, and perhaps db4 if you use the Fedora 10 SRPM for subversion.
You shouldn't have to build from source. If you can get the RPM, then you can use yum to install it:
In the case of Subversion, you should be able to get v1.6.3 here: http://www.collab.net/downloads/subversion/redhat.html
In the case of httpd, you should be able to get v2.2.11 here: http://mirror.cloudera.com/apache/httpd/binaries/rpm/