In theory, yes. T-Mobile is actually the carrier for the iPhone in Germany. Keep in mind, however, that unlocking an iPhone completely voids its warranty, and if anything happens to it, the only recourse is to purchase a new iPhone. Apple will not service a broken iPhone if it is unlocked.
Of course, the iPhone 3G and/or the original iPhone will take any normal sim card; the 3G iPhone will take the 3G sim as well.
You can put any SIM card in an unlocked cell phone.
no, you dont. you can jailbreak your iphone and run it on tmobile's network, if you have a tmobile sim card. but on tmobile, you cant have 3g speeds, only 2g.
Yes
To unlock your iPhone with you Tmobile SIM card I would suggest you goto easyiphoneunlocker.com they have a very easy to use tool to unlock and jailbreak your iphone. I was able to unlock my iPhone 4S within in 10 minutes with no issues.
An Apple iPhone 3GS can be purcased unlocked without a SIM card and used with a local carrier's SIM card. Once purchased it is as simple as inserting a SIM card from the carrier of your choice.
all iphones have a sim slot but on the original iphone the customer cannot easily access it whereas the 3G iphone has the sim card and a sim card ejector tool How can I access my verizon iphone 4 sim card slot that doesn't have a sim tray
Assuming the SIM card is the correct size for the iPhone (ie not a micro SIM) - there's no reason why not. Since you say it's unlocked - it should accept any networks SIM card.
yes. once an iphone is universally unlocked it will work.
Yes you can. You can put any tmobile sim card into any tmobile or unlocked phone and it will work perfectly. Although you may need to add some features to your plan :)
yes you can if ur iphone is unlocked you may have a choice of any sort of simcard but if its locked you can only have that type of simcard
No, You cannot use reliance CDMA sim card (or) any other CDMA card sim card on Apple iphone 4s. Any GSM Sim card will work on factory unlocked Apple iphone 4s but not CDMA sim ONLY IN INDIA.