Cisco has a Second Life
Just read this very interesting InformationWeek article by Mitch Wagner. It seems, in addition IBM, Cisco has a significant presence in Second Life. Most interesting paragraph in the article:

By the way, I've found SF Designs to be a great source for men's business clothes. I bought about 10 identical suits from them in different colors (including one goofy one in red and green for Christmastime, with a realistically cheezy Christmas necktie). They're on-sale now for L$300 each, that's a about a buck and a quarter US$.

On the other hand, I have read enough words of caution: Second Life is not easy for novice users, it does crash, security of conversations is at the same level as IM, etc. I am sure we will hear a lot of discussion on the topic. I also believe that there is an opportunity for a new player to do a much better execution than Second Life and produce a real business usable tool. We are in the very early stages ... time will tell.