No because even if it is unlocked sprint works on a CDMA and AT&T works on a gsm signal it's like trying to use AM on FM radio only
No. The iPhone 3GS is sadly a GSM only phone, so it cannot function on Sprint (or Verizon's) bandwidths.
yes. once an iphone is universally unlocked it will work.
No
No
Sure you can unlock your iPhone 3gs but before that you have to jailbreak iPhone 3gs.
You either have to purchase an unlocked iPhone or jailbreak and unlock it yourself after you purchase it. This process does void any manufacturer warranty.
Dont get it sorry
unlocked only means it can be activated on any service, not that the phone is any better, when the iphone came out it was only available on one service, unlocked means you can activate it on any service
Yes it is now possible to unlock all versions of iPhone 3G and 3GS
Yes indeed! The iPhone 3Gs is still available to buy new, and Apple actually continues making them, infact every iPhone 3Gs bought at this time has already got ios 4.0.1 intsalled on it! but by now ios 4.0.2 is already out, so why keep 4.0.1? ;)
Yes
Yes it does.