Slash Command(includes usage info): "/looklock"
For help, type "/looklock help"

This addon makes it possible to bind a key to enter a state where
moving the mouse rotates the character, without holding down a button.
While in this mode, the mouse buttons can be set to behave
differently, or to strafe.

--GUI Information--
This addon supports both Khaos and Cosmos, which will give you graphical configuration options, for every option this addon has. You can obtain Cosmos and Khaos from http://www.cosmosui.org