I took the plunge into Second Life about a year ago. It's amazing to me just how real this virtual world can be. What I found in my exploration was that Second Life (for me anyway) was incredibly time-consuming.
With that said--I think that virtual worlds are amazing...and I do believe that as educators we have an opportunity to use these virtual worlds in a host of different educational venues. Vicki Davis (the world's most amazing teacher) has been working with her freshmen to build a virtual world that teaches digital citizenship. Imagine the possibilities of teaching other subjects via virtual worlds like second life...what a great way to keep our students engaged.
I have so many new things that I want to incorporate into my teaching this year; adding virtual worlds to that would be awesome. Let's see where the year takes us!