My due eurocents having just returned from Northern Italy.

Bkgd:
iPhone 1: US ATT iphone 3G; firmware 3.1.3, Modem FW: 05.12.01 Spirit Jailbreak
iPhone 2: (not usable): US ATT iphone 3GS; firmware 4.1, Jailbroken, unsure which method. MODEM FIRMWARE IS NOT YET UNLOCKED FOR THIS FIRMWARE SO YOU CAN'T USE IT WITHOUT ATT.

What I did for phone service:
1. While waiting for departure, took out US ATT SIM and put it in a safe place.
2. Upon landing in Milan, took the train (Milan Malpensa Express (8 EU) to Milano Stazione Centrale. Walked into the Vodaphone store on main floor and babbled "Scusi, parla inglese?". This yeilded a small scowl and a "no". Me: "vorrei comprare un SIM card". "no". Strike 1.
3. We were waiting for our train to Venice and I spotted a TIM store, which is what I really wanted on the ground level, or it may have been the mezzo level, I don't recall. It wasn't open when first arrived. The young italian ladies spoke broken english, but much better than my italian. With a change of tactic, I opened with "Mi dispiace, no parlo bene italiano. Avete SIM cards, prepaid?". "yes, we do". Whew. She offered a menu of choices, but all I wanted was the sim with data/internet and a little talk time for reservations. I text through google voice, which uses data. I think I paid 14 euro for a SIM with 5 EU credit and data. Popped it in and got internet immediately. You do need to provide a credit card and passport. Some canadians with an iphone 4 walked in during the transaction. She seemed a little upset that my package was different and asked why. I realized today that the 4 uses a microsim, rather than standard.
4. I put the sim in and rebooted the phone. Internet worked immediately. I got some SMS messages (via iphone SMS) that said that my line would be activated later in the day. I used the internet the whole way to venice and throughout our trip, even tethering to a laptop. Received a wrong # call later in the week, so the phone must have been working, but I never needed to use it. I did test the # by calling my italian # via google voice from a tethered connection through the phone (if that sounds confusing, it is).
5. Mobile data usage was low for a week, I think around 100 MB. The allotment for the plan is 250 MB / Week. Pretty good coverage in Venice, Parma, Milan and trains in between. Even signal in the Milan Metro! Location services were kinda spotty, and I usually needed a clear view of the sky to get google maps working with my position. The maps were always available which was great.
6. Got back on the plane to JFK. Put ATT SIM back in and now I'm back to pretrip status.

For iPhone 2: Unable to use TIM SIM. Just put the international calling plan on it and didn't use it except on WiFi. This was a backup emergency plan in case we got separated. She could call me and I could call her, and we could receive calls from the US at her number.

For the future: Hopefully the DevTeam will release the newer firmware unlocks soon so both iphones can be put on TIM for future visits. I'm also going to get a cheapie quadband unlocked to use as a backup. Crazy as it sounds, lots of people in Milan had 2 cell phones.

Interesting.

I am thinking of jailbreaking my Iphone 3Gs for my trip to Italy since it will have been replaced with my new phone by then... so I don't care if it doesn't "recover"

(I do have to figure out how to change a sim card on this phone )

Thanks for this. Would the same sim card work in an unlocked blackberry?

OK, NOW let's get down to the real issue./ Just how much did you save vs. using the international calling plan and for your calls ONLY? Hundreds? Thousands? A few bucks?

Be careful with the 3GS. Downgrading firmware and unlocking are trickier than with the 3G. While you won't brick it, it may be impossible to unlock, depending on whether you have upgraded. I used redmondpie.com extensively. Some info is correct, some spurious.

Dukey - AT&T's discount package allowing 100 MB (OP's reported usage in the week) per a month is $120 in addition to the cost of the user's existing domestic data plan. So rough calculation of saving would be $120- €14 ~ $100 for the week.

I recently took a jailbroken iPhone with me to Italy, got a TIM card in Rome and it didn't work. I was later told that the phone had to be jailbroken with Italian software in order for it to work in Italy. 40 euro down the drain

Seamus, Thanks for the proxy calculation. That's about what I estimate as well. If you factor in time to do all the stuff, it's probably a break even for a single trip, however the ability to use it repeatedly worldwide on multiple trips completely changes the monetary value. It's not that the money would put me out, but I find the data roaming charges egregious.

Look11, I can't speak to your problem. Mine was not JB with Italian software so I think that isn't the issue. I wish I would have chatted with the Canadians to see how they unlocked their phone. My guess is that you had modem FW that ultrasn0w doesn't unlock. I'd like to know what iOS, modem FW, and whether you had ultrasn0w.

There is an important distinction between Jailbreaking (installing non apple software (aka Cydia)) and Unlocking which uses software to allow other carriers (ultrasn0w).

Oh, one more thing. There is an App called iTreni from the app store that I highly recommend. It's an interface for the Trenitalia website the I found incredibly useful in searching before buying tickets and planning. http://itunes.apple.com/us/app/itreni/id325961750?mt=8

Re look11 and iPhone that was jailbroken not working -- there are two different items at play, namely jailbreak and unlocked.

A phone that has been jailbreaked has been "hacked" such that non Apple apps can be installed and restricted areas of the flash storage are accessible.

However, a phone that is jailbreaked alone can not be used on other than original carrier (likely AT&T). To be used with any carrier, the phone must be unlocked. And to be unlocked, one first must jailbreak the phone so that the unlock "process" can be done.

So, I suspect that your phone did not worked because it was jailbroken but not unlocked.

Great explanation, CharlieCA. I'd add that it applies only to Apple iPhone, not the non-iPhone GSM quad band phones that get recommended here all the time. For those all you need is for the device to be unlocked so it can be used with any service provider.

Thanks for this info. I'll have to ask my friend, who lent me the phone, as I am COMPLETELY clueless about this! I was just SO disappointed to not be able to use the stupid thing Oh, well, it all worked out just fine with the old phone card.