An anonymous reader writes "Second Life is a virtual world, maintained through a combination of client software and hosting servers. It has the unusual quality that nearly all of the content is user-provided. It is also unusual in that Linden Labs recently announced the release of its client software as open source. This is something that is rarely, if ever, done in commercial MMO apps. This article introduces the client (or "viewer" in Linden terminology) and explores the Second Life development environment."