http://hipchat.com http://hipchat.com is pretty quick to set up - it has web, desktop, and mobile clients - they also seem to have experimental support for XMPP

http://hipchat.com http://hipchat.com is pretty quick to set up - it has web, desktop, and mobile clients - they also seem to have experimental support for XMPP/Jabber (http://blog.hipchat.com/2011/04/25/experimental-support-for-xmppjabber/ http://blog.hipchat.com/2011/04/25/experimental-support-for-...), which would let you use Adium to connect.