This will give you a list of all the rooms you or the specified nickname has an access level to and tell you what access. If no nick is given, it will give you the list for the nick you are using. You must identify for the nick before you may see the listchans info.
/msg nickserv listchans JoeUser
/msg nickserv listchans
This is a very useful command. If you have forgotten which rooms you were given access to, you can check. You can also see if anyone has added you to a room without telling you. If you use many rooms, it can become easy to forget one, so listchans can serve as a reminder.