I came across another great online Lighting Diagram creation. It's made by Sylights and I'm pretty sure it will make it easy for you to create and share lighting diagrams.
Created by Paris-based photographers Pierre-Jean Quilleré and Olivier Lance, the service is quite simple and easy to use, with the main pages being a diagram editor and a browse section to check out other photographers’ diagrams.
Yes, this web page gives you the opportunity to share your own lighting diagrams and to use some of the already shared ones by some of the users.
The site is designed quite well, and the editor is actually easy and fun to use. You simply right-click to add elements to the canvas, and then drag, resize, and rotate them as needed.
The editor uses HTML5 and CSS3, so it should work fine almost all the devices on the market. On iPhone the only real issue is the lack of right click but maybe on an update version of the page the creators will gives us double click instead of the right click. This way would be much easier to use the page on the iPhone.
But as you may know for the iPhone you still have the great application called Strobox and it's also free.
On another article posted here at Lighting Mods called "Lighting Setup Diagrams with and without Photoshop are possible!" you can check other ways to create your Lighting Diagrams.