Hi Spark Core guys.
You may have already tried MEASURING THE TEMPERATURE example at http://docs.spark.io/examples/ which is great way to know how to use the temperature sensor.
I just created very simple iPhone App which connect the sensor via the Cloud API and blogged the whole process at http://d.hatena.ne.jp/higepon/20140915/1410784693.
You can also download whole source code github.
The iPhone App is written in Swift, so easier to understand than Objective-C 
Any questions are welcomed!
Will you make a project with more analog/digital inputs and outputs? Because I’m not sure how to decompose the JSON response in Swift yet.
Temperature+lightsensor as inputs and RGB LED as output for example.
That would be an awesome tutorial!
https://github.com/SwiftyJSON/SwiftyJSON this might come in handy maybe. Doing some tutorials about it myself now, but it’s still not that easy 
I made a simple app and seem to have got the RGB light working. Also made a Spark Swift Class so it’s cleaner and easier to do requests. The files are a little all over the place because of a submodule problem but just look for UIControls and don’t forget the SparkModel.swift file.
Check it out at: https://github.com/YannisDC/SparkCore
Got a UISlider working, a UISwitch and a UIButton since they look the most usefull to me.
Next thing up is checking the variables from the SparkCore for initialisation of the UI-elements.
If we all work together on this we can make an awesome framework for using the SparkCore/SparkPhoton as THE IoT device 
note I used other peoples code to build of from so big thanks to @will, @bko, @higepon and probably many others.
Yahoo! Nothing like a simple interface 