private instant messenger service

We want to have an instant message client on our site but we just want
our own private messenger that doesn't communicate with AIM, twitter,
etc. So basically something akin to google talk but that users can
only use to talk with on our site. Any one have a good plugin or gem
to help us out? We can't use juggernaut because Heroku doesn't like
(very) long running processes.

Unless you are polling you probably need a long running process. You
might be able to do long polling as a rails metal thing, but I still
thing you need some thing coordinating when the long polling requests
should complete.