I'm on Fedora 9 (64-bit). If I do
yum install subversion
it installs version 1.4 or so.

How can I fix this so that yum will install the very latest stable version of subversion, i.e, 1.6.1 at the time of writing?

Many thanks,
D

Try

yum --showduplicates list subversion

to see what's in the repos you have available. I don't have an F9 platform to check on any more.

When installing software from the distributions packaging tools and the default software repositories you don't always get the latest version.
There are quite a few 3rd party 'yum repos' out there.
Some places have a policy to never use 3rd party modules due to the potential of packaging/library version conflicts.
I have had great success using Fedora's EPEL 'yum repos' for getting more up2date versions of software.
If any of the '3rd party repos' don't have the latest version your after the next thing is to grab the SRPM for the package and modify it to build the newer version. This can be a little less than trivial but a very worthy learning experience.

rpmforge certainly has 1.6.2 for CentOS 5, so I'd be surprised if they didn't have at least the same for F9

Yeah, the problem is that rpmforge doesn't have a reference for Fedora 9 / yum.

So the question is, how do I configure yum (i.e, add the appropriate repository) so that it will pick up the latest version of svn?

It looks like rpmforge havent got a FC 9 specific repos.

Here is a link with some info for you.
https://fedoraproject.org/wiki/OtherRepositories

I think one problem you may run into is that in FC world FC9 is getting a bit old now and some repos may have dropped support already.

If what you want is not available on a repos somewhere then you really have 2 choices left.
Upgrade to latest FC or grab the Source RPM for the package you want out of a newer FC release and recompile/backport it to FC9.

Or remove the current version with yum and just install from source.