If you maintain many branches in your favorite version control system it is essential understand which branch for which indented.
In SVN you can put README on same level as trunk/branches/features dirs. How about DVCS?
You can maintain ChangeLog. But with this approach it is hard get breif view that done in all branches (if you maintain different long lived releases changelogs between them they can be slightly different).
In open source project info about branches usually can be found on project wiki, so stored separately from VCS. I think this is bad thing. When you clone project you also need aceess to wikis.