Before I set off to the US I did a bit of research and overall people seems to make it seem difficult to do this but when I arrived in San Francisco I stopped at the AT&T store on Market & 3rd and asked for a PrePaid SIM. The nice sales assistant asked what phone I was using and I showed her my iPhone 4. She said we don’t support that so can’t give you a refund but when I said I knew what I was doing she set about the paperwork.
The one advantage of using an AT&T store is that there is no setting up to do on line the account will be active by the time you leave the store. I picked the 500Mb data option $25 (the minimum for a new SIM) and $15 for voice on the 10 cents a minute plan.
So after spending $40 I plugged in the SIM and away I went. What I should have done is use the free WiFi in the store to access unlockit.co.nz which provides the APN details for AT&T and 100s of other networks around the globe. Download and install the AT&T settings and the data services work perfectly.
The only problem I had was that texts are very expensive 20 cents each and I should have taken the $5 200 package for my wife’s phone.
But having a fully working iPhone with proper data and not having to worry about roaming charges was worth the hassle.
By the way I redirected our UK phones (on O2) to my UK Vonage number **21*+44divert no# and from there to my Google Voice number and on to the new number I didn’t yet know for my local phone number has worked well and Google voice takes messages and sends / email to allow you to hear the messages over the data network.
Before leaving I the UK I should have gone to http://unlockit.co.nz on my iPhone (you need to do this at the airport before you leave the UK or when attached to a WiFi network in the US) press continue and the CUSTOM APN and select the CARRIER option which will show you a long list of carriers roll down to USA I think I just used AT&T as the option if that doesn’t work try one of the other options for AT&T – push the button that says CREATE PROFILE this will load the profile on your phone – click INSTALL when asked to do so and then click INSTALL NOW you will be asked for you passcode if you have one set up.
When you leave the US you need to delete this PROFILE to do that go to SETTINGS and at the top you will see CONFIGURATION PROFILES select the APN Carries Settings item and then REMOVE and you phone will be ready to work with your UK SIM.
If your travelling to the US this certainly seemed to work for me.
UPDATE the http://unlockit.co.nz site now has lots of US AT&T options I suggest using the AT&T (PAYG) which looks the same as the “cingular” one that others recommend
