My friend purchased an iPhone 4 that cannot be unlocked so the store sold him a new cell phone service called H2O Wireless. You simply pop in the sim card and it works without needing any unlock or chip. Does anybody have a clue on how it works?
H₂O doesn't provide a network of its own. Instead, it purchases bandwidth in bulk from a carrier, in this case AT&T, and provides prepaid service using the carriers network.
So your friends phone isn't unlocked, but works just fine on the carrier network that its locked to.