For those that are not familiar with LighTrac, it's an IOS/Android App that will show you what the sun angle and elevation will be at any given address and date. LighTrac is $4.99 in the Apple App store, Amazon App Store and Android Google App Store.
Of course the whole point of LighTrac and SunCalc and other similar Apps is to be able to plan a shoot so you are not going to be shooting directly into the sun for the front shot.
Vladimir's SunCalc.net website is very cool. It works beautifully on iPads, laptops, large screen desktops and even small 7" tablets like iPad Mini and Kindle Fire. It works on SmartPhones too but on small screens like the iPhone 4s there is just too much stuff smushed on the screen to be useful. Perhaps on the larger Samsung smartphones with a larger screen it works better.
I should mention that SunCalc doesn't show you the sun elevation like LighTrac does but to me that not a show stopper.
I think SunCalc is a great example of how great web apps can be done that will run on any device and in this time of transition from desktop/laptop to mobile devices you really want these apps to be available everywhere.
Hats off to Vladimir!