Yes, but it is difficult without the right tools, go to your local At and t store and have them do it.
No!
Yes it can be swapped. I actually swapped my razr's sim card to my iphone. Nothing happened. It works perfectly.
No
If your 3GS is locked, you can't insert a SIM card.
any AT&T phone that can take that sort of sim card.
You put a sim card in it.
Yes, Yes you can.
Yes, but only if you unlock you iphone
As long as it is AT&T, yes.
you can take a sim from any phone and put it into an iPhone. they will all work the same, just make sure you call you phone company to let them know your going to switch phones
From your blackberry ,copy all your contacts to your sim card. Then remove the sim from your bnlackberry and put it inside the iphone. On your iphone do the import sim contacts. To give you the step by step provess on how to do the sim importing go to the link http://nice-to-know-about-iphone.blogspot.com and search for the topic "how to import sim contacts" hope it will help
Yes, you can use a Flight 2 SIM card in an iPhone 3G, provided the SIM card is compatible with the network frequencies supported by the iPhone. The iPhone 3G is unlocked or locked to a network that supports the SIM card. Ensure that the SIM card is properly activated and configured for use in the device.