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Currently the only way is to take a micro-sim from another carrier and stick it in and see if it works.

Otherwise there is no software out there to see if your phone is unlocked.
 
Yes, chop it down to size and as long as you have the right dimensions it should work in 2G mode only... Since T-Mobile's 3G network operates on a frequency not supported by the iPhone.
 
If your iphone is unlocked, when you first activate it (or restore it) using iTunes, you will get a message: "Congratulations, your iphone is unlocked." This is in addition to the "Congratulations, your iPhone is activated" message.
 
If your iphone is unlocked, when you first activate it (or restore it) using iTunes, you will get a message: "Congratulations, your iphone is unlocked." This is in addition to the "Congratulations, your iPhone is activated" message.

Really?? My factory unlocked iPhone never mentioned anything about being "unlocked" when I activated it... however I have verified that it is in fact unlocked.

I know the way we can tell in Canada is by the receipt we received. Unlocked iPhones you receive a receipt stating no carrier on it, a separate receipt for the micro-sim card.
 
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