Looking to get an iphone

I'm thinking about getting an iphone for airsoft. I need something like a walkie talkie that I can talk to people over short distances non-stop for free or really really low price. Might spend many hours a week on the phone. But it wouldn't be near a wifi hotspot so the phones would have to either use the cell network or transmit directly.

If they transmit directly, what's the range of a LAN wifi network?

If the range is no further than a couple hundred feet, is there a way to increase the range of the iphones wireless with an aftermarket antennae extension and/or increase antennae power output?

I also need an app that can give me the precise locations of my friends, like within 50m. A source I found says Iphone GPS is only accurate to 500m. Is that true and does the Iphone transmit to the tower to get that data? If so, is it free? I may want to have it on a lot.

On such an app I'd like to be able to share information with friends. Such as uploading a custom map, fitting it to the right scale, seeing where my friends are on the map, and being able to draw arrows on the map that get shared with friends.

I've done some research but i get alot of this http://www.google.com.hk/search?hl=...23072l526947l0l527213l21l11l0l0l0l0l0l0ll0l0#
(chinese firewall message)

what country are you researching from? the link you provided looks like google china?

If you have Skype installed on both devices, you could chat for endless hours for free without using cell minutes. But if you're not using minutes or WiFi, you're using cellular data. Don't know how much data your cell plan gives you each month.

As for the GPS, 500m is probably accurate while driving at highway speeds. When stationary, though, I can use the FindMyPhone app to tell where in the house my iPhone and iPad are. As I walk around my little 1500 sq ft house, I can sometimes watch the dot move around on the map. With a clear view of the sky, I'd say it's easily accurate down to less than 50'.

Yes, posting from China, this is for when I get back to the states though.

I don't have a plan atm, just prepaid cellphone. I think my friends are on at&t. Not sure if iphone is unlockable. So ill probably go with the same provider.

Good news about the GPS though.

Thank you.