Today I learned a new trick from http://www.pgrs.net/2008/1/23/remove-files-that-are-not-in-subversion that I have been able to adapt to a couple different situations.
svn revert un-modifies files, but it leaves new files lying around as cruft. How do I get rid of them?
This command does the trick:
svn st | grep ^\? | cut -c 2- | xargs rm
Also, if you have added directories, you should also run this command