The iPad 2 is only slightly thicker than a pencil. Photo: Jim Merithew/Wired.com

When you’re shopping for an iPad 2, you have a dozen configurations to choose from, and some recent discoveries will make this decision much easier for you.

To configure your iPad 2, you have 12 options as you decide on color, storage and, most importantly, data connection — 3G + Wi-Fi, or Wi-Fi-only.

It turns out that if you’re one of the millions of people who own an Android phone or an iPhone, you don’t need a 3G model, which will save you a big chunk of cash. Here’s why.

Smartphone hotspots

All U.S. iPhones (upgraded to the latest version of iOS) and the vast majority of Android smartphones now officially support wireless-hotspot capability, which turns the handset into a Wi-Fi connection that can be shared with multiple devices, including the iPad.

So if you go with a Wi-Fi-only model and you want to hop on a cellular connection, you can activate the hotspot option on your smartphone through your carrier, pay $20 per month and connect the iPad to that.

That’s not as seamless as having 3G built into the iPad, but it will save you the extra $130 you’d plunk down on a 3G model. Plus, you’d have to pay at least $15 a month just to use an iPad’s 3G connection anyway.

Jailbreaking for free hotspots

If you’re down with getting a little dirty, you can use your Android phone or iPhone as a hotspot without paying monthly fees by hacking your device.

For Android phones, you just have to root (aka jailbreak) the device with a tool called Unrevoked. For rooted Android phones, there are unauthorized apps called Wireless Tether and Barnacle, which offer free hotspot utilities. You can also flash your device and install CyanogenMod, a different Android skin that includes a built-in hotspot feature. Presto.

For the iPhone, all you have to do is jailbreak with any of the tools out there. (Do note that if you do update to the latest version of iOS, you can’t jailbreak yet.) Jailbreaking will install the Cydia app, which gives you access to the underground Cydia app store. There, you can download the unauthorized app MyWi, which costs a one-time fee of $20, and doesn’t charge you monthly.

GPS Transplant

The Wi-Fi iPad doesn’t have built-in GPS, but if you want to use that beautiful Maps app for navigation, you still don’t need a 3G iPad, so long as you have an iPhone. It turns out that if you hotspot with an iPhone, the connection transfers the GPS to the iPad.

Just connect the iPad to the iPhone’s hotspot, then launch the Maps app, and you’ll see the blue dot tracking your location.

(We’re not sure if this works when hotspotting with an Android phone — if you can confirm, let us know in the comments.)

3G FaceTime

Another surprise is that if you turn your smartphone into a wireless hotspot, you can connect to it with your iPad 2 and use FaceTime videoconferencing.

That’s interesting because typically you can’t use FaceTime over a 3G connection; it’s supposed to only work on a Wi-Fi connection. Because a hotspot shows up as a Wi-Fi connection, you’re basically tricking the iPad 2 into using a 3G connection for FaceTime.