I rather suspect that Second Life is not going to be suitable as a library tool for most of us in the near future. The technical specifications required to run it and the expertise to put it together are still relatively high. There are certainly library staff like Kate Sinclair (who I mentioned in an earlier post) who are involved in SL projects. But how to run a library presence?
It will, I suspect remain the preserve of the the academic/national-type library. Carrie Pennell of Harvard University wrote about her experiences in setting up a presence in SL here. The British Library also seems set to enter LindedLand.