Second Life is an interesting thing. I think it really comes down to what your target market is. This will determine if there is any value for your business there.
For example, I don't myself know of too many business professionals that are active residents in Second Life, but I do know a number of college students. Second Life seems to me something that is going to be dominated by the geeks, academia and generally a younger audience. If your ideal market is characteristic of that, you could do very well to get involved.
I myself have never participated in second life. I am to involved in my first life to manage a second one.
