Ever heard the term "kludge"? It refers to a workaround, a cobbled-together solution to a problem. Usually, it ain't pretty, but it works.
Collect3's CoBrowser is a kludge, a way around Apple's limitation on apps that enable tethering. With it, a Wi-Fi iPad can tap an iPhone's 3G connectivity--no jailbreaking required. It's extremely limited, and it ain't pretty, but it works.
Just to clarify, CoBrowser doesn't actually tether your iPad to your iPhone. Instead, it shares the latter's screen with the former, and then only for Web browsing. Before you shake your head in dismay, consider the value in being able to surf on your iPad even when there's no Wi-Fi available. Pretty tempting, right?
To get started, install the $1.99 app on both your devices, then enable Bluetooth on both--it's how CoBrowser communicates. Run the app on your iPhone and tap Host Session; then run it on your iPad and tap Join Session. Presto! You're connected.
Once this happens, CoBrowser launches its own custom browser (one that's virtually identical to Safari)--on both devices. As you'll quickly discover, the iPhone is actually sharing its screen with the iPad; that's the "tethering" trick CoBrowser pulls off. So as you browse on your iPhone, you see everything writ large on the iPad.
It works the other way, too--you can navigate the browser on your iPad as well--but with one very irksome limitation: whenever you open a page or tap a link on the iPad, an "Accept Incoming Request" alert appears on your iPhone, and you have to tap to confirm it. Every single time.
That definitely diminishes the overall experience, which is why you may prefer to do the navigating on your iPhone and only the reading on your iPad. What's more, the CoBrowser browser offers no way to import your existing bookmarks, another irksome limitation. And if you want to do anything other than browsing--check e-mail, stream a video, etc.--you can forget it.
Like I said, it's a kludge. But it works, and does so for the extremely affordable price of 2 bucks. To put that in some perspective, AT&T charges an extra $20 per month for traditional tethering. If you own an iPhone and a Wi-Fi iPad, you may find CoBrowser the answer to a prayer. Or half the answer, anyway.