"People looking to unlock their iPhone 3Gs should avoid the hardware-based SIMable option, according to a member of the unofficial iPhone Dev Team, producers of PwnageTool. The coder notes that the modern 3G baseband chip has been designed around SIM-based hardware hacks, and so any attempt at them must use fake identifiers. This information is said to "leak" into cellular networks, generating errors.
While a hack could in theory work under this scheme, the errors are recorded by telecom companies, and may be considered tampering in a company's network. In countries like Germany, as a result, a person could allegedly face up to three years in prison, and in the US, it may fall under legislation designed to combat terrorism.
There is little alternative at present however, as utlities like PwnageTool are only able to jailbreak an iPhone 3G, not unlock it for use on unauthorized carriers."
MacNN | Dev Team: SIMable hack for iPhone 3G is bogus