Quoted from SecondLife/Linden Lab
A lot of the Second Life development work currently in progress is focused on strengthening and expanding the Second Life Grid — a globally interconnected grid with clients and servers published and managed by different groups.
At Linden Lab, we have always been strong advocates of the use of open standards and the advantages of using open source products. Though the Second Life Grid makes abundant use of non-standard technologies, we rely on open standards and open source implementations when appropriate and available.
Releasing the source is our invitation to the world to help build this global space for communication, business, and entertainment. We are eager to work with the community and businesses to further our vision of the Second Life Grid.
You can join us immediately by joining the mailing list, identifying and reporting bugs, or getting the source to compile a viewer on your own.
Linden Lab has made the source code for the Second Life Viewer available to everyone. Talented developers from around the world are now able to collaborate with Linden Lab to refine and enhance the experience for all residents of the Second Life Grid."
SecondLife Open Source link h3r3