If you use Pidgin, an Instant Messenger that can connect to STO and Champions Online and allow you to speak to fleet/friends etc without needing to log in. Pidgin can tell you every custom channel that exists across both games.
just be careful. the chat channels are global across all sewrvers( including champions) so if your play both you can keep in touch with your friends on one or ther other. there were so many REDALERT channels while all three servers were up it got confusing. lol.