If you are interested in investigating Second Life they have lots of information you can read, before you have to sign up, here.  You will also find tutorials and links to their blog, wiki and forums.

This video gives an overview of educational uses of Second Life.  There are plenty of other videos available on YouTube or Teacher Tube.  These mostly relate to tertiary education - you have to be over 18 to use Second Life, however there is a Teen Second Life site for 13-18 year olds.

If it all sounds too much you can Get a first life instead!