You are referring to 3G. Yes it is capable of doing everything that WiFi is capable of. You need to get a 3G plan from your service carrier.
the iphone also has 3g capability's allowing you to browse the internet or use web apps anywhere the itouch needs to be on a wifi network to do any of that
Any where that WiFi is available. There are no restrictions.
How Do I get my wifi network back on my iphone
No.
No...you don't need wifi for the American idol app for iPhone.
yes, you can just use wifi access to use the Internet on your iPhone
yes
yes
ATT recently (Sept, 2014) announced that it will introduce WiFi calling for iPhone in 2015.
“How do I get wifi for my IPHONE, I already have internet service at home but it's not wireless”
Yes, you can use your iPhone 3G(S) to access the Internet if you have an available WiFi connection.
Go into Settings, WiFi... that's it, pick the one you want to connect to.