iPhone unlocking and jailbreaking is the lingo used in while making iPhone to use other Network and insalling iphone apps from stores other than Apple app store.
let me explain these two terms
JailBreaking : Breaking the phone software jail. so that it can install apps from diffrent stores other than app store.
Unlocking: as i phone comes with a specific provider lock. to break the lock so that i can be used on other GSM network, called unlocking..
from the very first phone called IPHone 2g, jailbreaking and unlocking are the common terms.
iPhone 2g-> 2 years back Zibri launched the ZipPhone, a very good unlocking and jailbreaking tool. very userFriendly tool, but he didn't release the software after the 2g and 1.1.4 os verson. and sold his blog to somebody (ziphone.org)
iPhone 3g -> Iphone 3g came with 2.0 software with many secruity against unlocking and jailbreaking. But iphone dev team broke the security and released the tools for both mac and windows os. tools name were
it requires two mandatory files..
bl39.bin 3.9 BootLoader
bl46.bin 4.6 BootLoader
they vary according to your iPhone and os.
Iphone 3GS -> With launch of 3gs apple released 3rd version of Os ie. 3.0 and third hardware device. Now when you talk about 3gs. we always talk about 3.0 version operating system.
now unlocking and jailbreaking has been categorised as following.
iPhone 2g with 3.0 or 3.0.1
iPhone 3g with 3.0 or 3.0.1
iPhone 3gs with 3.0 or 3.0.1
The first jailbreaking of iPhone 3gs having 3.0 os was released by "George Hotz"( a teenager hacker). You can download the tool from http://purplera1n.com/ which was release by above hacker.
After that Iphone dev team also released some version to break the phone.