+1  A: 

You can generate md5 password files using apache's htpasswd utility (located in the bin directory).

Then, in your httpd.conf:

<Location /svn>
     DAV svn
     SVNParentPath "repo path"
     AuthType Basic
     AuthName "Repository"
     AuthUserFile "password file path"
     Require valid-user
     SVNListParentPath on #if you want a repository listing for the whole svn directory
</Location>

This will require user authentication, and only username/password combinations located in the password file (from htpasswd) will be accepted for access.

In addition, you can also specify read-only access to everyone, but use the password file for commits, etc by the following (within the location tag):

<LimitExcept GET PROPFIND OPTIONS REPORT>
     Require valid-user
</LimitExcept>

If I'm understanding what you need, this should solve it for user-level access.

EDIT:

I forgot to mention, that if you do use a password file, make sure it is not accessible through the web (ie, no alias or directory are assigned in apache where it is stored).

Chris S
I already have a .htpasswd file and that all works fine.The problem occurs when I try to use subversion's path-based access control, using the svnaccess.conf file that I listed above.My gut feeling is telling me that this the above configuration is ALMOST correct, and I'm either leaving out an Apache directive, or I am missing something in how I have written out the svnaccess.conf file to get what I need.
kaybenleroll