You can but you will have to install the three app by going to this site I.three.com.au
Sure you can unlock your iPhone 3gs but before that you have to jailbreak iPhone 3gs.
yes. once an iphone is universally unlocked it will work.
No
Dont get it sorry
No
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? ;)
iPhone 3gs
iPhone 3GS
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.
The iPhone 3GS was never offered with Verizon. Most got them with AT&T, and got their phones unlocked so they can use the phone with other service providers.