SECOND LIFE
This is the most famous site on Internet to chat and interact with peoople all over the world.Actually,this is more than a site, it is a way of life.
You need a fast connection and a good PC.Registration is required and the download of the program,too.
Once ready,you have the chance to create your avatar,or alter ego and interact in different scenarios... highly recommended.
http://secondlife.com/

SECOND LIFE LINKS
This is in Portuguese and features all the news and what is happening on SL(SECOND LIFE) world.There are different places to go,together with the links.
http://secondlife.blig.ig.com.br/