Here's a sample config that I use
<Location /svn>
DAV svn
SVNParentPath /var/svn
# ServerName svn.vudesign.net
AuthType Basic
AuthName "Subversion repository"
AuthUserFile /etc/svnpasswd
Require valid-user
Order Deny,Allow
Deny from all
Allow from XXX.XXX.XX.XXX
Allow from XX.XX.XX.XXX
Allow from XXX.XX.XX.XX
Allow from XX.XX.XX.XX
Allow from localhost
</Location>
all the x's are merely IP addresses, blocked out for semi-obvious reasons.
Whilst on the subject of subversion, I can heartily recommend Edgewall software's Trac, an issue tracking system and wiki that interfaces nicely with subversion (repo browsing, automatic update of tickets with checkin comments etc.) it needs python running as cgi or mod_python installed as well as a few other things, but it's well worth it.