I’ve searched high and low for a service that allows you to tether your iPhone on a grandfathered unlimited AT&T data plan without jailbreaking. To add tethering to an AT&T plan, it requires giving up my beloved grandfathered unlimited data, which I don’t want to do.
There have been few options in the past that allow for tethering without jailbreaking your iOS device. One option, which I tried with limited success in the past is iProxy, an open source iOS app that allows tethering. Unfortunately, it is not actively maintained. Also, if you are not already a developer, $100 is a lot to shell out for an iOS developer account (needed to deploy the app) on a gamble for an unmaintained app. I had limited success using this when I tried it with iOS 4.
Tether.com came up with the genius idea of building the iOS client side app for tethering in HTML5 and Mobile Safari. For $30/year, this is a much more reasonable cost for the casual mobile tethering user.
In order to use the Tether.com service, download the app to your computer. The purpose of the app is to create the ad-hoc connection that your iPhone will connect to. Downloading the application for OS X (they also have Windows support) is simple and creates the required ad-hoc network automatically when run. A nice feature is that it restores the wifi connection to its previous state when the app is closed, making the experience about as good as possible for dealing with the network.
After using Tether.app, connect to the ad-hoc network with your iPhone, and visit Tether.com/web. The web application shows a status of the connection and does its job nicely.
I have successfully used the app on several trips and it was mostly reliable. Occasionally I would have issues making the connection from computer to iPhone, but for the most part it worked well. One caveat of using tether.com is that you cannot let your phone idle and lock. This is because iOS power management will kill your wifi and active adhoc network to conserve power. To get around this, I typically turn off auto-lock and try and keep my phone plugged in.
Overall I like tether.com’s ingenious tethering solution. While it isn’t ideal for the frequent traveler, it works well for limited use when you’re in a bind and need internet on your computer.