The following process will setup subversion so that users can checkout via webdav (e.g. svn co http://foo). The example assumes the user has root privileges via sudo on beaver.codehaus.org.
Edit /usr/local/apache-2/conf/svn-dav.conf to include:
# how to authenticate a user
AuthName "FOO Repo"
# For any operations other than these, require an authenticated user.
<LimitExcept GET PROPFIND OPTIONS REPORT>
Require group FOO
Add the apache user to your project's unix group FOO
Bounce the Apache server to reload its configuration.