I finally got my group to switch from SourceSafe to Subversion. Unfortunately, my manager still wants to use exclusive locks on every single file. So I set the svn:needs-lock
To see what locks you and others hold, you can use TortoiseSVN → Check for Modifications.... Locally held lock tokens show up immediately. To check for locks held by others (and to see if any of your locks are broken or stolen) you need to click on Check Repository.