eBay or Craigslist
Unless its an iPhone then it would be no.
You can check to see if your iPhone is unlocked by inserting a SIM from a different service provider and try to make a call, if its successful. Your iPhone is unlocked.
yes. once an iphone is universally unlocked it will work.
Yes, you can now buy the iPhone 4S unlocked direct from the Apple website
There are several providers of unlocking services for iPhones - both on location in Orlando, but if you don't have an unlocked iPhone yet, you could check out unlocked iphones on www.unlockediphones.net.
600
No it has to be unlocked
No!
Yes
Yes, it is possible to buy an iPhone that is unlocked. An unlocked iPhone is not tied to a specific carrier, so you can use it with different mobile networks by inserting a compatible SIM card. You can purchase unlocked iPhones directly from Apple, authorized retailers, or certified refurbished sellers.
Yes, you need an unlocked & Jailbroken iPhone. Which isn't cheap.
The iphone will be restored using the last backup so your info will be saved and it will still be unlocked.