IBM's Social Computing group have published an interesting paper entitled "Acquiring a Professional 'Second Life': Problems and Prospects for the Use of Virtual Worlds in Business".  It details the trials that the group have done with a variety of business users and outlines both the issues met and the benefits to be had.  Rather like the Forterra 'Recipe For Success' paper that I wrote about, the most useful aspect are the user anecdotes and quotes.  For example "Comparing other technologies, big step up. Can probably adequately replace F2F for some tasks.", or "I really do think there's potential in using Second Life to collaborate in teams".  It's worth a read.