I can see how various commercial and academic enterprises would see the Facebook environment as offering a captive audience and an opportunity to make their presence felt where many people devote a good deal of their time. But commercial overtures feel intrusive and an academic presence feels slightly incongruous and superfluous. Personallly, because I see Facebook as a place for fairly frivollous social interaction with friends whom one cannot see physically and nothing else, there will be other more appropriate places where this kind of academic information might be better accessed or disseminated. I can see how others might see more potential in the site. RSS feeds from libraries or SMS alerts would be more fitting for me, if anything.
That said, perhaps a library of department 'fan page' might engender a sense of community among users and establish relationships that wouldn't necessarily occur otherwise.