What confused me here is that currently Mentors don't actually need to go to the developer's server for the dynamic lighting feature: my screenshot above is from the normal server, where I have it enabled.
There is a thread on the Mentor forum explaining what the current situation is with Dynamic Lighting and how you can make use of it, Axel: <a href="http://community.roll20.net/discussion/2863/dynamic-lighting-for-mentors#Item_1" rel="nofollow">http://community.roll20.net/discussion/2863/dynamic-lighting-for-mentors#Item_1</a>
For everyone else in this thread, sorry for the confusion. As with anything related to Roll20, only things you hear officially from a Mod or the Dev Team should be taken as fact, especially regarding new features.
Dynamic Lighting is still only available to Mentors. We don't have an exact ETA on when it will be released to anyone else, as we have several other features (mobile support and character sheets among them) that we are currently working on in parallel.