The OnLook Viewer is a simplified virtual world browser for OpenSimulator environments based off the Singularity Viewer.
It's User Interface (UI) is intended to give a distractionless user experience for the casual virtual world visitor, while the fully detailed user options remain available by changing the user preferences.

OnLook can be used for any OpenSimulator virtual environment, independent of their configuration. While OnLook strives to keep up with Singularity, it does not aim at staying compatible with Second Life. OnLook is not an approved TPV viewer for SecondLife though, and it should not be used there.

The OnLook viewer is maintained by Diva Canto, Liru Faers and Nebadon Izumi. Contributions are very welcome, especially those that are aligned with the goal of the project: server-side-defined UI.

OnLook is available in Github.

Download Here (links point to the original sources):

OnLook viewer, directly from Github.

Singularity Viewer .

FireStorm Viewer (recommended as "the best" usability and graphic experience)
Choose the 64 bits viewer for SL & Opensim or the 32 bits version if your system is not 64 bits.