You can get them online from various stores. I've looked around, and via Amazon you have access to a good selection (New and Used) at reasonable prices, usually plus free shipping. You can also get a MicroSIM cutter through Amazon, which you'll need to cut a regular size SIM card down to MicroSIM size.
The best iPhone 4 for frequent travelers abroad is a Quadband GSM iPhone 4, also termed a World Phone because you can use it just about almost anywhere in the world. This also makes it a good choice if you live in a country where the iPhone is not yet available, because it's configured to work with all four globally used GSM frequency bands (850, 900, 1,800, and 1,900MHz.)
And at long last the classy and funky "White" iPhone 4 is here. Black can get so boring! It's available with 16GB of memory, which is ample for most of us. Of course it has all the functionality that you're used to with the black iPhone 4.
Click Here For: White iPhone 4 16GB Unlocked? Factory Unlocked? No Commitment ? Jailbreaking? What????????
There are a variety of terms relating to the commitment made when buying an iPhone 4. Let me try and get rid of some of the confusion....
Locked
In the USA Apple have appointed two network carriers for the iPhone, AT&T and Verizon. If you buy an iPhone in an Apple store you have to choose one of these two, and the phone is then locked to that carrier. Obviously a phone bought in an appointed carrier's store is locked to its network. This means that you can use your handset only with that specific carrier network. In addition, AT&T uses GSM technology and Verizon uses CDMA, and the two are incompatible.
Factory Unlocked
This is also termed: legally unlocked / never locked / sim-free. It quite simply means that the phone has never been locked to any network. If you get a phone that is factory unlocked it comes new without being tied to any network, without restrictions, and you can choose your own carrier.
Factory unlocked iPhone 4s are configured to GSM technology, so if you use it in the States, the two big carriers to choose from are AT&T and T-Mobile. Bear in mind that T-Mobile is not an Apple-approved carrier, which mainly means that you will have to trim your T-Mobile SIM card down to MicroSIM size (which is what's used with the GSM iPhone 4).
When traveling abroad, you can buy prepaid SIM cards from local GSM-based carriers, but again you will have to trim the SIM card (easily done with a MicroSIM cutter, which is cheap to buy.)
Unlocked (Not By Factory) and Jailbreaking
On July 26, a ruling by the U.S. Library of Congress made it legal for iPhone owners in the States to jailbreak and/or unlock their handsets. As a result, many people are weighing up whether to unlock or jailbreak their iPhones.
Jailbreaking an iphone allows you to remove the limitations imposed by Apple and install third party themes and applications not available from Apple.
Unlocking your iPhone means making it usable on cellphone networks other than the carriers approved by Apple. The approved carriers, AT&T and Verizon, don't unlock phones, so you have to look beyond them.
Answers to questions surrounding these two processes are not quite clear-cut. A search on the internet will uncover many forums where unlocking/jailbreaking and related issues are discussed. In the final analysis it's up to you to choose, so...go "Google" it.
No Commitment
Don't get confused between the terms No Commitment and Unlocked. No Commitment means "pay as you go" but in the States your phone will still be locked to either AT&T or Verizon.
