no
iPhone 3gs are more roundish and without Siri. The edges instead of being straight are round. The iPhone 4g has square edges without Siri. The iPhone 4s is just like the 4g instead it has Siri. The iPhone 5 is longer and has Siri. The iPhone (original) has round corners and is small. Same with the iPhone 2. If you have a iPhone or iPhone 2 you can replace them. Also, the iPhone 3gs is not out so you cannot buy it anymore. Only the 4, 4s and 5 are out. They will be getting rid of the iPhone 4 soon.
I dont think you can use siri only the iphone 4 can by holding the home button
I would say it stands for Siri. More specifically "Siri Voice Recognition", since the regular iPhone 4 does not have Siri (by default). But I can't find any official documentation to back up this answer.
iPhone 3gs
iPhone 3GS
the iphone 3gs replaced the iphone 3g.
Dose the iphone 3gs have a radio
yes it has Siri
If you mean,' Do iPhone 3GS's have Verizonservice?'No, not anymore, as of 17/10/2011 you can only get the iPhone 3GS on AT&T!
no why do you think its called trading in?
You can unlock your iPhone 3Gs anywhere if you have internet:)