The IPhone 4 can normally not be used for all carriers, the only option to use a different carrier / simcard in the iPhone is when you unlock the phone. Today a new Unlock service is released: Permanent IMEI unlock ( Factory unlock). The unlocking is permanent. Even if the iPhone will be upgraded, it remains unlocked. The unlocking works for all iPhone: 3G/3GS /4/4S in any iOS version. It is even completed with guarantee.
This new unlock option will surely be very popular, because even though its quite pricey, the benefits are wonderful: No jailbreaking required, you can update your iPhone without worries without being scared the phone will re-lock, use any sim card, any carrier worldwide in your iPhone without any hassle.
Unlocking iPhone 4 via IMEI can be a choice for use in iPhone 4 with the favorite carrier. Not all iPhones can be unlocked, but with this new method, people are free to determine which carrier they want to use with their iPhone. The permanent result won’t give any difficulties in the future. With the unlocking system via IMEI, the iPhone can be used with any carrier that suits the users’ need and budget.
Here is the benefit Unlock iPhone via IMEI
-Unlock works on all iPhone models and versions
-No Warranty issues: usual software unlocks will void the phone's warranty. IMEI unlocks do not.
-Update your iOS without hassle or worries
-No loss of features, iTunes compatible
-Baseband in dependent: it doesn't matter which base band your iPhone has.
To put it simple: your iPhone will stay unlocked forever.
For more information about the IMEI Unlock your iPhone visit http://www.unlockaniphone.org/