I have mentioned MeeboMe as a possible cheap low tech way to provide basic chat reference in hospital libraries, depending on your hospital's firewall. The Shifted Librarian has created a list of libraries using MeeeboMe on the Library Success Wiki. Currently there are ten libraries using it, not just public libraries either! Four colleges/universities are using it including one medical library. The University of Colorado Denver and Health Sciences Center - Denison Memorial Library has a link on their main page to "Ask a Librarian - Live Online Reference" when clicked on directs you to their Meebo information.

I would be very interested to hear from anybody at Denison Memorial Library to hear about their experiences with Meebo and it usage.