Much like past versions of Apple's iPhone, hacks for the iPhone 3G generally consist of software modifications that allow owners to unlock, jailbreak or install third party iPhone applications onto their phones. These modifications are not sanctioned by Apple, and will void the warranty.

When the original iPhone was released, customers activated their phone service over the web using iTunes. For the iPhone 3G, Apple required customers to activate their phones in store.Gizmodo: AT&T Memo to Retail Managers Shows iPhone 3G Policy The policy was enacted to make it more difficult to unlock the new iPhone.ComputerWorld: FAQ: The new iPhone brings changes... (June 11, 2008)

The iPhone Dev Team's iPhone hacking tool, called Pwnage 2.0, was released on July 19, 2008Official iPhone Dev Team Blog: Thanks for waiting :) (July 20, 2008). It is designed specifically for the iPhone 2.0 firmware and fully jailbreaks and unlocks original iPhones upgraded to 2.0 firmware. However, it only jailbreaks the iPhone 3G. The Dev Team is still working on a final release ready for the general public.Gizmodo: iPhone OS 2.0 Unlocked (July 10, 2008)