Hi
First, I'll assume that you mean commit when you write checkin (the short command is ci but the long command is commit).
Use "svn ls" to list the files in the repo under the current directory.
You can use "svn ls -v" for extra information or "svn ls --username <user>" to list only one users files.
If I understand you correctly, I don't think that's the write permissions is the right approach. you can lock a file - maybe that's what you're looking for?
Anyways, it's always useful to check "svn help" and "svn help <command>"
and also try
http://svnbook.red-bean.com/