Long range wireless questions

We are planning a project for electronics club but had a few questions in regards to wireless connections.

We are starting with 2 remote control cars and proofing out our system before we take to the air and try to build quadcopters. The plan is(or was) to use Arduino Mega 2560's with a motorshield and wifi shield on each of the cars, then an arduino uno + wifi shield on the remote controller.

We want an operational range of at least 1 mile, which obviously we will not get out of a standard wifi shield. Now the question is, what is the easiest way to obtain this? We were looking into the xBee wifi shields but noticed they are discontinued and we cannot get them from anywhere. Any suggestions?

This?

These work for me right out of the box
http://shop.ciseco.co.uk/xrf-wireless-rf-radio-uart-rs232-serial-data-module-xbee-shape-arduino-pic-etc/

Thanks for the responses guys, I will present the options to our group and see what they prefer.

The XRF guy is a direct replacement for the xBee then? I would still need to get a SD-wireless shield to put it on correct?

Just another question, Why does the Wireless SD shield state it is capable of 100' indoors, 300' outdoors when it doesn't even have an receiver on it? wouldn't that be dictated by the module connected to it, which in the case of an XBee or one of the above modules would be several miles?

sorry i dont know anything about the wireless sd shield but the xrf's have a carrier board with 0.1" interface pins designed to plug straight into a XINO board which is just a clone arduino board

Probably best for you to go to a site like below (or google) and see what people there are doing for long range control.

Even if range wasn't an issue with WiFi, the fact that the WiFi shield only allows you to join an existing network (not create one) might be.