The Subversion people have a links list which references a ton of material related to Subversion including management and different web interfaces.
I haven't used it, but Submin might be what you're looking for.
If you're looking for simple repository browsing mod_dav_svn is minimal and works.
Trac was already suggested, but that has more bug-tracking-wiki-project-management features, but very little administration of SVN out of the box.
