I should only use an Arduino, a shield, an iPhone and the WiFi network.
I made some search on some forums and most people suggested me to use a “web browser” in iPhone as a simple solution. I think i have to code the web browser in php and from that browser I should be able to send some commands from iPhone to the Arduino. I am planning to buy a Wifly shield or Ethernet Shield and try that “web browser” trick since i don’t know how to use Touchosc App to send signals without Processing.
Is it possible to use a single browser in iPhone to send some commands to Arduino without using a server?
And most important for me is to decide which shield i should buy for this purpose.
Which shield should i go for in my case? A Wifly shield or an Ethernet Shield? What is the difference?
You probably never have done a web project (based on how you write about coding a browser in PHP). Integrating an Arduino into a WiFi network is possible although I would not suggest that to be your first arduino project.
If you only wanna use an Arduino, one shield, your iPhone and a WiFi-Network (and nothing else), you must use some sort of WiFi adapter on your Arduino (WiFly shield or something similar) because for the Ethernet shield you also must have a wired network (you probably have that but you did not include it into the list of things that may be used). From the programming aspect both, the WiFly shield and the Ethernet shield, provide example sketches how to use them as an HTTP server (that’s what a browser is connecting to). Please keep in mind you don’t get the comfort of a web server (p.e. apache) on an Arduino, you have to do the whole HTTP protocol yourself. This usually results in very simple web services and the like and no funky shining web page.
Normally a “real” web server is providing the web pages (including images), doing all the user interface stuff and after getting all the necessary information from the user it’s calling the web service (or just a socket connection) on the Arduino to react and do some hardware stuff.
To answer your question about the difference between an Ethernet shield and a WiFly shield: The WiFly shield is connecting your Arduino to your Wireless Network (using radio transmission). The Ethernet shield connects to a wired network, so you have use a cable between the Arduino and some network device as a router or switch. The Ethernet shield give you more flexibility but you need a free Ethernet port to connect it to.