The creators of the massive Second Life virtual world on Monday released the user program to the open-source community in a bid to get other developers to modify and enhance the software.

Source code for Second Life's Viewer application -- the program subscribers use to access and play the game -- has been posted to a Linden Lab server and is available under the GNU General Public License. A second license also will be available for developers who want to reserve the right to create proprietary Viewer extensions.

"We have a responsibility to improve and to grow Second Life as rapidly as possible," said Philip Rosedale, CEO of Linden Lab. "We were the first virtual world to enable content creators to own the rights to the intellectual property they create. Now we're placing the Viewer's development into the hands of residents and developers as well."

Linden Lab said it will add certain code changes and enhancements to the official version, which will be downloadable only from the Second Life site. Code created outside of Linden Lab "will be thoroughly reviewed," the company said, but third-party Viewer projects won't be supported by Linden Lab.

"Open sourcing is the most important decision we've made in seven years of Second Life development," said Cory Ondrejka, the company's chief technology officer, in a separate statement. "We will still continue Viewer development ourselves, but now the community can add its contributions, insights, and experiences. We don't know exactly which projects will emerge, but this is part of the vibrancy that makes Second Life so compelling."

According to Linden Lab, the initial open-source projects may include bug fixes, new "skins" for the Viewer, and support for additional multimedia formats.

More information on the Viewer source code and licensing can be found on the Second Life site.