In front-end not for now. But there are plans to implement such things. I remember a feature request regarding "Let admins see who is logged in atm" Please go to the bug-tracker http://dev.sourcefabric.org to vote for existing tickets or create a new one.
Reason I wanted to know about this I've had some strange things happening. For instance, all Friday's playlists moved to Sunday, people adding corrupt media.
I couldn't figure out from logs when such happens or who was logged in at the time. As a result I can't tell if someone is messing up or airtime is misbehaving.
Please let me know if you are aware of these things or how to fix them.