Education costs money. Ignorance costs more.
I've been spending some time in SL lately. I agree there's not a lot you'd want to refer students to at present and there's too much replication of RL. However, I recently went to a small-group meeting on Eduserv Island which I thought was pleasant (http://www.youtube.com/watch?v=8Ioh8uxTh7s) and productive and I think Genome Island deserves some kind of mention in dispatches (http://slurl.com/secondlife/Genome/127/128/49/). Microbiology Island anyone?
Thanks Peter. I haven't had much time for SL recently, but my conclusion so far based on very limited knowledge is that it is a conferencing tool rather than a teaching tool, at least at present.