How to send iPhone location data to Arduino Ethernet?

I’m assuming there are various ways of doing this. So far I’ve found an app that can send iPhone location data to a server script (SendLocation) and I’m assuming the Arduino Ethernet can be that server with a script on it, but I’m not sure as to which server library makes the most sense to use for this: WebServer, webduino, or something else? Is there an even better option?

What I’m trying to make is a “when-I’ll-be-home” kitchen “clock” that will dial down LED lights as I get closer to home, maybe also blink at the speed I’m moving.

Where is the link to that app? What kind of server does it expect? A webserver?

Do you know how port forwarding and DynDNS works so your Arduino is visible from the Internet? Did you already study the manual of your router about these topics?