Eric and I talked about this in GFR podcast #303 .
Lets be clear: this a work around, not a solution. But a lot of people have a substantial investment in their iOS devices (the cost of the device plus apps) and this is a way to switch to TING for low cost voice and data plans while maintaining most of your investment until TING gets an iPhone/iPad.
First of all, I bought a refurbished LG Optimus S from TING, the cheapest phone with mobile hotspot.
I ported my iPhone number to Google Voice (excellent tutorials on setting up GV: Using Google Voice on your Ting phone : Ting Help & Support http://ow.ly/mvfZ3 ) and had a new telephone number issued to the TING phone. I routed my GV number (old iPhone number) to my TING phone using the Google Voice dashboard. This allows me to have a PERMANENT cellphone number, regardless of cell carrier…or no carrier at all.
I turned off my AT&T service to the iPhone and iPad. Essentially I turned my iPhone into an iTouch. I then installed Google voice on all of my devices.
I don't make or receive many voice calls, so it's not too much of a pain to have the LG for voice calls. Particularly since I can use my computer to make GV calls as well as see or hear any text or voicemails that come in on GV (my old cellphone number).
So, when I'm around work or the house, the iDevices connect on my local wifi routers. When I'm in the car, they use the LG TING phone as a hotspot. As long as I remember to turn off the hotspot when I get to work or at home, forcing my iDevices to switch back to the wifi networks, I don't run up much of a TING bill.
Because I'm using GV for my telephone number, the TING LG stays plugged-in out in the car most of the time. If my GV rings, I'll catch it on the computer or Skype back a return call when I hear their voicemail.
Since my old voice/data/messaging bill was between $150-175 dollars per month PLUS the separate data plan for the iPad ($25/month), I'm saving BIG money without too much trouble to myself. My wife shares the account using a cheap TING flip phone, since she mostly talks on the phone and doesn't use SMS or Internet very much.
Like I say, it's a workaround, not a solution. But to save $1200 a year, I'll deal with it. If the iPhone ever gives up the ghost and if TING doesn't get an iPhone, I might switch to a highend Android device. But for now, this is the most cost effect use of my investment I could come up with.
Follow the directions in this post @ gigaom to learn how to set up your Google Voice number (your old cellphone number) for VOiP (Voice over internet protocol). You'll need to download and install two apps: GV Connect and Talkatone from the Apple APP Store. Together, they cost about $3.00, but are ad supported. You can pay a $1.99/month fee to get ad free and a few other upgrades.
Once set up, Google Voice and your iOS handset will work as VOiP or through your TING phone account. With this addition, the Android phone that acts as a hotspot is just that: a hotspot. You shouldn't need it for calls, SMS or internet directly. It can all be done from your iOS device.